On the dusty road outside Dharavi, India's biggest slum, where children run barefoot through piles of rubbish and families sleep under canvas sheets, a smart black car is parked. Through tinted windows, reclining on the beige leather seat, a smiling woman waves to the cameras jostling for position outside. She smooths down her navy twinset, runs her manicured nails through her blow-dried hair, and thrusts open the door.
Thus began the reinvention of Valerie Trierweiler, former first lady of France, as she visited the slum during a two-day trip to Mumbai with the charity Action Against Hunger this week. It marked her first public appearance since President Francois Hollande announced their split on Saturday, after news of his affair with actress Julie Gayet sparked an international media frenzy.
Though she was reportedly hospitalised for "rest and some tests" after news of the affair broke, Trierweiler, 48, who began her relationship with President Hollande in 2005, looked none the worse for recent events. Instead, as she toured the slum with her bodyguard, she was photographed smiling and speaking freely to reporters, telling them: "Don't worry about me; I have time to think about the future." Later, at a briefing by the pool at her five-star hotel, she provided gossipy details about "low blows", "back stabbings" and "betrayals" at the Elysee Palace.
During her visit, Trierweiler launched a foundation to fight childhood malnutrition, a cause that she said "catch[es] my heart". Her generosity must, of course, be praised; but so, too, must the PR value of her trip, days after her unceremonious ejection from the Elysee Palace. Well-executed and perfectly timed, it has directed the attention of the media away from her personal life and towards her newfound ambitions in the charitable sphere. No longer the spurned first lady, Trierweiler is recast as a benevolent ambassador, reaching out to those less fortunate despite her own travails.
Indeed, Patrick Biancone, her chief of staff, has dropped hints that she believes she is destined to follow in the footsteps of another great ambassador: Diana, Princess of Wales. "She has not gone back to being a simple citizen," he told reporters in India. "She is an ex-first lady. That gives her a special status."
Mme Trierweiler is by no means the first figure with "special status" to devote herself to charitable work (or, as the move is more crudely described, to "do a Diana"). She joins a long line of celebrity activists - Bob Geldof, Bono, Sting, Angelina Jolie - who have used their fame to raise the profile of a cause. But her new role is not without its risks. In finding herself compared to the People's Princess, whose charitable work included highlighting the dangers of land mines with the Halo Trust and raising more than pounds 100 million for HIV and Aids patients in Africa, she must tread a careful line - or she risks further damage to her reputation.
Though Trierweiler's visit to India had been organised months ago, many expected her to withdraw. James Herring, co-founder of Taylor Herring PR, says going ahead was a surprising decision. "It seems rather hasty; a knee-jerk reaction," he says. "Cynics might even see this as a tactical snub against the other woman. While Gayet is out and about on the red carpet, Trierweiler is doing something meaningful. I'd advise her to take some time, reflect and deal with the turbulent couple of weeks - and not just jump into rebuilding her personal brand."
Trierweiler might do well to heed his words. Fellow celebrities who have forged a career in the third sector - particularly those trying to salvage their reputation or re-enter the spotlight after an absence - have met with mixed results.
Some, like George Clooney, who set up his own charity to highlight human rights atrocities in the Darfur region of Sudan, have been praised for their actions. Clooney, who has visited the area and spoken to victims of rape and torture, has given much-needed money and publicity to the cause. Joanna Lumley, who became the face of the Justice for Gurkhas campaign in 2008, achieved similar success, with the Home Office acceding to the veterans' demands for permission to settle in Britain the following year.
Others, such as Jolie - who raised eyebrows when she first got involved with charitable work in 2001 - have managed to turn around public perceptions of their activism.
Critics initially accused her of indulging in too many photo ops and failing to make a real difference, but 10 years later, her campaign continues. To date, Jolie has built 10 schools in Cambodia, funded education programmes for children affected by disaster, and been appointed as Special Envoy to the UN High Commission for Refugees.
"If your support for a charity is genuine, you can be an amazing help," says David Read, managing director of Neon Management, whose clients include Pamela Anderson and Martine McCutcheon. "It can definitely help your image, too, if it's done properly. We encourage our guys to go for just one charity; choose carefully and get behind it, instead of trying to be a patron of many but not showing interest in any."
Geri Halliwell, the former Spice Girl, was a UN Population Fund representative in the Noughties, but critics said her work seemed mostly to comprise footage for her BBC documentary, Geri's World Walkabout. David Arquette, the American actor and ex-husband of Friends star Courtney Cox, spent two days sitting in a plastic box atop Madison Square Garden in order to raise awareness of world hunger. Both were accused of taking part in headline-grabbing stunts.
Lauren Lunn-Farrow, director of PR agency Lunn Farrow Media, says it is usually "obvious" whether a celebrity is fully engaged in the cause they're claiming to support. "When Geri left the Spice Girls and wanted to reinvent herself as a 'serious' celebrity, she put on a pencil skirt, put a scarf round her neck and went to the UN," she says. "I'm not saying she didn't care about everything she was representing, but you could tell that she hadn't done enough research. In my view, doing something like that is career suicide." There is a danger, too, for the charity that associates itself with a celebrity on the wrong end of a news story. Lindsay Lohan, the US actress with high-profile problems, has done few favours with her voluntary work: she also soured her relationship with animal rights activists PETA after wearing fur. Similarly, the causes championed by Naomi Campbell, who has spoken out against racism in fashion and poverty in Brazil, weren't helped when the model pleaded guilty to assault in 2008.
It's a long way from the vision of the original celebrity activist, Audrey Hepburn, who supported Unicef throughout her career in the Fifties. "The 'Third World' is a term I don't like very much, because we're all one world," said the film star, who spent her retirement working for Unicef projects in Africa. "I want people to know that the largest part of humanity is suffering."
The recent rise in "charitable" celebrities, however, is linked to the UN's "Goodwill Ambassador" scheme, which recruits high-profile figures to draw attention to its mission. Among the names on its extensive list are Annie Lennox and Naomi Watts (campaigning against HIV and Aids), David Beckham and Vanessa Redgrave (Unicef) and Nicole Kidman (gender equality). If her trip to India is a sign of things to come, Mme Trierweiler could soon be among them.
Some words of wisdom, then, for the former first lady as she returns to Paris. "Doing a Diana" requires more - far more - than one tour around a slum. The months ahead will not be easy. Be committed, informed and interested. Above all, learn from those who have gone before you, say the experts.
"When Diana and Charles split up, she couldn't get a normal job, so she used her profile to help others," says Lunn-Farrow. "You could tell she was genuine - just look at the moral values she's passed on to Princes William and Harry. She really wanted to help others, and when she did, she did it properly."