Constantine was privately educated at boarding schools including Queen's Gate School in South Kensington, London and the £20,000-per-year St Mary's School in Wantage, Oxfordshire which was run by nuns. Her time at St Mary's School was described by herself as "miserable" due to her homesickness and insecurity, meaning she was not able to make friends. She was first sent to boarding school at 11 years of age, and has recalled her first night away from home: "I sobbed uncontrollably into my pillow."

In mid 2007, Constantine spoke about how she received a letter from St Mary's School, inviting her to come back to the school to talk about her career and success to current pupils. Constantine immediately declined the offer with a four-letter refusal and wrote "No fucking way" on the letter she had received. Her personal assistant was then left to deal with the situation, who wrongly sent the inviting letter with the hand-written sentence by Constantine, back to the school. The boarding school then wrote a shocked letter back, explaining that they will not let Constantine near the school again.

Constantine originally did a year of Montessori training after she had left school but she then moved onto other projects such as studying sculpture in Brussels: "lost my virginity, went a bit mad." commented Constantine. Constantine had taught children for three years, and also worked as a shop girl for Harrods. She found the job, in her own words, "boring" and even tried shop lifting for more excitement, but she now has admiration for shop girls. Constantine's love for horses had inspired her to become a mounted policewoman in London, but was deterred when she was required to do four years walking the beat. She wrote a book about present giving, which prompted The Daily Telegraph to write an unpleasant article implying she had never done a day's work in her life, something which deeply upset her. She has stated defiantly "I've always worked."

She is now best-known as a fashion guru and style advisor, where her fashion career started when she worked for many years under fashion designer Giorgio Armani as a shop girl in America. She later came back to London with the hope of securing a job with Armani but ended up working for designers such as Richard James, Patrick Cox, Alistair Blair and John Galliano which gained her an even greater understanding of fashion, providing an in depth knowledge of how a garment progresses from a sketch. She then started working with the British Brain and Spine Foundation and consequently met the sports editor of The Daily Telegraph. Whilst doing a piece for GMTV, he asked Constantine to report the women's World Cup Final in cricket on finding out that it was her passion. She proceeded to write about cars and then fashion.

In 1994 she first met Trinny Woodall at a party hosted by David, Viscount Linley. Though they did not like each other at first, the two women proceeded to write Ready to Wear, a weekly style guide for The Daily Telegraph which ran successfully for seven years. The column promoted affordable high-street fashion and they used themselves to illustrate which clothing suited which figure. Constantine and Woodall also became the co-founders of Ready2shop.com, a dot-com, but the business venture had failed, and investors subsequently lost a reputed £10 million. It was during their time running the internet business that they had a serious argument that almost ended their friendship.

Constantine made her television debut when Granada Sky Broadcasting signed her and Woodall to present a daytime shopping show called Ready to Wear, and they soon released their first fashion advice book, Ready 2 Dress in 2000. The book was unsuccessful and resulted in the pulping of 13,000 copies. Soon after the start of their television career, they secured a frequent makeover slot on the show Richard & Judy. It ensured that they had further exposure in television and gained attention from Jane Root, controller of BBC Two, who took a risk and signed them up after their book and their internet business had been unmitigated disasters.

2001...2003

Constantine began co-hosting What Not to Wear with Trinny Woodall in 2001, which required using her fashion advice and expertise in order to reform participants' appearances and fashion style. Constantine and Woodall hosted What Not to Wear until 2005 where they instantly became renowned for their tactile behaviour with the participants, direct advice, and frequently referring to breasts as tits which has become something of a trademark. Never one to hold back, a notorious moment arose when Constantine spontaneously pulled a female candidate's underwear down during filming as her knicker line was visible. Critics of What Not to Wear argued that the duo were too patronising to their subjects, a claim which they strongly disagree with. Constantine said that the comments come "from the heart", and insists that their subjects "see we have a genuine love of women. We love women and they can see that. Women just know." She also stated "Ultimately, what we're doing is giving people confidence. We're probably the only people who have an opinion, who care how ordinary people dress. No one at Vogue magazine gives a shit. They work with the designers, it's more creative and artistic ... they are creating something beautiful. But they don't care about how their readers end up looking ... whereas we do!" The show made Constantine and Woodall household names and are now known together as Trinny and Susannah. One reporter has simply referred to Constantine as "the one with 'big tits'." Constantine and Woodall have even considered taking insurance out on their partnership should something unforeseen happen, although Constantine was against the move.

Constantine has the belief that "anyone can achieve style. It doesn't matter who you are or where you're from." She also says that she finds dressing other women easy, but finds it difficult when dressing herself. Constantine and Woodall share the belief that dressing to flatter body shape is vital, stating "For us, it’s all about shape, and how that is going to cure a bodily defect. We’re like clothing doctors."

During her time co-hosting What Not to Wear for five series, she and Woodall gained recognition for their work on the show, winning a Royal Television Society Award in 2002 for being the best factual presenters. In 2002, Constantine provided Jeremy Clarkson on a celebrity version of What Not to Wear. After Clarkson appeared on the show, Nasir Khan stated "I'd rather eat my own hair than shop with these two [Constantine and Woodall] again". Adding to its success, the show was nominated for the Features Award at the BAFTAS in both 2002 and 2003. On the show Big Impression, impressionist Ronni Ancona took to spoofing Constantine's presenting techniques on What Not to Wear, just one of the shows on which Constantine's character has been spoofed.

For charity, in 2002 during the BBC's Children in Need programme, both Constantine and Woodall performed their own version of Madonna's hit single "Vogue" with a group of celebrity backing singers. They became the faces of Nescafé in 2003 in which they were featured in television advertisements promoting the brand of coffee. As part of their contract, Constantine and Woodall gave a Nescafé competition winner a £10,000 makeover.

2004...2005

Following a ratings success, What Not to Wear was promoted from BBC Two to BBC One in 2004 to be received by even larger audiences. The format was changed slightly, where there was a 60 minute show with two makeovers instead of a 30 minute show with only one makeover and also saw Constantine spending a day as one of her subjects. What Not to Wear soon gained her international fame when it was aired in countries such as Spain and Portugal as well as in the American continent.

Constantine appeared again on Children in Need in 2004, which included a special segment with her giving the fictional EastEnders characters Little Mo and Mo Harris a makeover à la What Not to Wear, commenting on them with her usual "no nonsense" approach. In 2005, Constantine voiced a robot version of herself in the science fiction series, Doctor Who. In the episode "Bad Wolf", Trine-e and Zu-Zana were two robots acting out a deadly futuristic version of What not to Wear, offering a makeover to Jack Harkness in a most gruesome form.

The Oprah Winfrey Show has also seen Constantine and Woodall appearing regularly as a makeover and style experts, where they gave fashion advice and guidelines on how to better overall appearances and giving numerous American women fashion makeovers. They also did an "Oprah bra and swimsuit intervention". Reflecting on differences between women's style in the UK and America, she stated that although there is not much difference "The Americans are slightly less adventurous," and that "American women are more open to change and slightly more receptive victims."

2006...present

In 2006, Constantine and Woodall moved from the BBC to ITV in a deal reputedly worth £1.2 million to start a new show, Trinny & Susannah Undress..., on October 3. The second series of Trinny & Susannah Undress... was transmitted in June 2007, and it maintained the format of series one which saw Constantine and Woodall advising couples who were finding problems within their marriage. Constantine found it warming that people could open up to them as confidantes, and also said "It's been fascinating to see how looking good and having faith in your appearance makes you into a sexier person, which makes you attractive to your partner again." Constantine stated in an interview that filming the show was very emotionally draining, and as a result, she often went home crying. The programme did not come without its critics who questioned the depth at which Constantine and Woodall could deal with serious issues raised during the programme. On October 16, 2006, they both appeared on NBC's The Today Show on which they performed makeovers on three women especially for the show.

The new series on ITV sees a change in format and confronts the main fashion issues in Britain which included Constantine being transformed into a seventy-year-old when exploring the theme of age. She stated that it took her four days to get over the sight of herself aged so drastically, and compared the feeling to having an "electric shock". Broadcasting was scheduled for November 7, 2007 and the programme is newly entitled Trinny & Susannah Undress The Nation. On November 5 and December 28, 2007 Constantine and Woodall appeared on Good Morning America and performed makeovers on three women for the show and gave style advice according to the women's shapes. They also reported on the fashion at the 80th Academy Awards especially for the show in 2008. Constantine and Woodall have dressed over 5,000 women as of 2007. With reference to their personal website, they state that their satisfaction remains with the many women they have helped and inspired and not so much with the success with book sales and viewing figures.

In 2003, when Constantine and Woodall were interviewed for the first time on Parkinson, actress Meg Ryan had a controversial interview with Michael Parkinson, which resulted in negative publicity for Ryan. Parkinson said that he felt Ryan's behaviour to his fellow guests Constantine and Woodall, whom she turned her back on, was "unforgivable".

To coincide with Constantine's move from the BBC to ITV1 in 2006, she co-launched an underwear range with Woodall called "Trinny and Susannah Magic Pants" which are made of nylon, produced to flatten the tummy, buttocks and thighs so that the areas appear slimmer. Constantine even wore them after giving birth to her third child. She currently co-writes a weekly column for The Sun with Woodall.

Online

The Guardian reports Trinny and Susannah are in a new online series - produced by t5m Studios - "What Trinny and Susannah Did Next is a mockumentary — an elaborately knowing spoof — part Alan Partridge, part The Office, part The Thick of It. There's even a touch of Borat."

"The cast consists of professional actors and standup comics, the dialogue is part-scripted, part-ad-libbed, and the overall effect is weirdly postmodern and surprisingly successful. The biggest surprise of all is Trinny and Susannah's acting ability, which is astonishingly convincing, even though, as they cheerfully point out, they're only playing hyperbolised versions of themselves."

Celebrity cameos are to include Lulu, David Guest, DJ Neil Fox, Vanessa Feltz and The Scissor Sisters.

Episode 1, part 1 airs Monday 21st June 2010 with daily updates, Mon-Thurs until July 16th, at www.TrinnyAndSusannahWhatTheyDidNext.com

An announcement was made that Constantine and Woodall were doing a tour to New Zealand and Australia where they made a series of public appearances at shopping malls owned by the Westfield Group to perform live styling sessions for the company's customers. Their appearances often attracted thousands of spectators. Before the tour, Constantine said "We don't know how New Zealanders dress but we are looking forward to getting over there and finding out."

Littlewoods

Constantine became the face of the home shopping company, Littlewoods Direct, with Woodall in 2006 as during its sponsorship of their ITV programme Trinny & Susannah Undress, orders quickly rose by thirty per cent. The pair produced a twelve page fashion advice section within the Littlewoods catalogue and made a booklet called The Golden Rules, which was distributed to all Littlewoods customers with fashion advice to suit a range of body shapes. They have also produced online style guidelines for Littlewoods.

The first series of Littlewoods television advertisements featured Constantine and Woodall as themselves dressed as two agents trying to rob a Littlewoods designer warehouse, which was followed by Christmas adverts in 2007. The £12 million advertising campaign is one of largest ever for a home shopping and internet-based company. Since the campaign began, Littlewoods' sales have risen by 18 per cent, with brand awareness and customers visiting the website rising as well.

On 20 September 2007, Constantine and Woodall launched their own exclusive Littlewoods women's clothing range which consists of trousers, coats and tops which like their underwear range, are designed to make certain areas appear slimmer. A series of eight dresses, cashmere knitwear, faux fur and sequinned shrugs also feature in the range. She commented "If you want to create a waist, there's a dress that's going to do that for you too. We've designed it very much around the female body." She also stated "It's not about what size you are, it's about how you can minimise or accentuate parts of your body with clothing. That's what we've created."

Books

Constantine has co-written several style advice books with her fashion partner Trinny Woodall, which have sold over an estimated 2.5 million copies worldwide. The fashion advice books have been number one bestsellers in Britain and the United States, appearing on both The Sunday Times bestseller list and The New York Times bestseller list, and have been translated throughout the world.

Their most successful book to date, What Not to Wear, was published in 2002 which displayed striking chapters such as "Big Tits", "No Tits" and "Big Bum" with fashion advice for each category. It became an instant bestseller with total sales reaching 670,000 copies, consequently outselling Jamie Oliver and Nigella Lawson. Before the prime book selling season, their book had sold 250,000 copies in Britain. The book was at one point selling 45,000 copies each week and sold 300,000 copies in just fifteen weeks, eventually making sales worth £8.7 million. Other success with the book includes winning a British Book Award in 2003 for the TV & Film Book of the Year. Despite the book becoming an instant hit, Constantine and Woodall were only given an advance of £10,000. It was then reported that Constantine and Woodall secured a £1 million book deal to write more of their fashion books.

The fashion duo's latest book, The Body Shape Bible, was published on September 18, 2007. Through a survey about different body shapes conducted amongst women, Constantine and Woodall were able to discover the twelve most common women's body shapes. They used this information to write The Body Shape Bible which highlights these twelve shapes which have all been named in ways such as 'cornet' or 'brick'. In the fashion advice book, women can interpret which shape they are, and can then be given adequate fashion advice on their own individual shape. A few pages in the book are also devoted to illustrating some of Constantine and Woodall's own fashion disasters.

Constantine grew up in an old priory in the Leicestershire village of Knipton and went hunting from the age of seven. She had a close relationship with her father, Joseph Constantine, who was successful in the property and shipping sectors, was an Old Etonian pupil and served in the Coldstream Guards. When she was young, Constantine would rely on her father for fashion advice and has commented that any style that she has, she learned from him. He was a talented artist and was offered worldwide art exhibitions, although too modest to accept. His death came suddenly and was a landmark for Constantine.

Constantine became a fixture in 1980s British gossip columns and newspapers as the result of her relationship with Princess Margaret's son, David, Viscount Linley which lasted for eight years. Princess Margaret thought highly of Constantine and even called her "my daughter-in-law". Constantine admitted that her relationship with Linley undeniably opened doors for her, but after they broke up, she was keen to put the episode behind her and become well-known in her own right. She has also had a relationship with Pakistan cricket captain Imran Khan, but she is now married to Danish entrepreneur and businessman Sten Bertelsen, who launched Death cigarettes, and with whom she has three children; Joe, Esme and CeCe. Lulu is godmother to one of her children, and she has also said "All my children have gay godfathers. I just love all gay men." Constantine and her family have recently bought a property in Sussex. Constantine is estimated to be worth £5 million.

After having her first child, Constantine suffered from severe postnatal depression and panic attacks. Upon discovering that she was pregnant for a third time, as well as being overcome with delight, she felt despair as it came at a time when best friend Trinny Woodall was struggling to conceive and undergoing IVF treatment. In an interview Constantine said that she "couldn't bear to tell her." A short time later however, Woodall became pregnant.

Constantine has spoken of the pressure to look good in public but affirms "We're as much in the business of dressing ourselves - but more importantly helping other women to do that." Constantine has admitted to a fear of growing older: "I just don't want to get old. Old women are invisible, and I don't want to be invisible," she has said.

In 2002, while on a visit to the Cannes film festival, Constantine and Woodall were the victims of gem thieves. The thieves broke into the villa on the French Riviera where they were staying, rendered Constantine and Woodall unconscious with chloroform, and then continued to steal money and jewellery. Carol Vorderman was involved in a feud with Constantine and Woodall in 2003. Vorderman commented harshly about the double-act, after they had called her an "overdone Eighties nightmare" and named Vorderman in their list of the 20 worst-dressed celebrities.