At her first wedding, to British actor Jonny Lee Miller when she was just 20, she wore black rubber trousers and a white T-shirt, upon which she had written the groom’s name in her blood. Before they separated, Jolie had a relationship with an actress and has since confirmed her bisexuality to interviewers.

　　Four years later, she married actor Billy Bob Thornton after a two-month courtship. The pair wore each other’s blood in phials around their necks and for their first anniversary, she bought him his-and-hers cemetery plots in a Louisiana graveyard. Yet 18 months later they abruptly split.

　　By now Jolie was established, winning the best-supporting actress Oscar for her role in Girl, Interrupted. After the ceremony, she scandalised onlookers by passionately kissing her brother, actor James Haven, and telling the world, “I’m so in love with him”. Haven, for his part, is an unmarried, born-again Christian. He said: “Because I’m so close to Angie, it’s like I’ve already got the perfect woman in my life, and it’s hard for anyone else to live up to that.”

　　But just as tongue-wagging about her eccentricities was peaking, Jolie – then 26 – began visiting refugee camps. Her first trip to Sierra Leone was revelatory. “I realised how completely naive I was to think I had a difficult life,” she recalled. “It was as if someone slapped me across the face and said, 'Oh, my God, you silly young woman from California, do you have any idea how difficult the world really is for so many people?’ ”

　　The turning point, says Morton, came when she made Tomb Raider in 2001. “It was her rehab role, the actress weaning herself off heroin in order to sustain the physical demands of the movie,” he says. “During the filming, she decided to adopt a Cambodian boy named Maddox. The infant changed her life, she began focusing on him and her growing role as an international advocate for the United Nations High Commissioner for Refugees.”

　　In 2005, she adopted Zahara from Ethiopia (Pax, from Vietnam, arrived in 2007), that same year making Mr &Mrs Smith. Within months, Jolie and Pitt were visiting Pakistan together to solicit aid donations after an earthquake, and within a year Jolie was pregnant.

　　Yet her new reputation as a husband-stealer had no effect on Jolie’s popularity. Polls showed her kudos continued to rise year on year, despite Aniston describing Jolie’s behaviour as “uncool”, and the couple announced their engagement in 2012. Pitt has downplayed any suggestions that there was a “dastardly affair” and insists that his break-up with Aniston was amicable.

　　An executive on the Hollywood magazine Variety said: “She is perceived as somewhat saint-like – a woman who only wants to do good in the world. When you’re in her presence, she’s so serene, you’d feel like an idiot asking a dumb question, such as: 'So, did you break up Jennifer Aniston’s home?’ ”

　　Dorie Clark, author of Reinventing You: Define Your Brand, Imagine Your Future, uses Jolie as a prime example of reinvention. “Because her negative brand attributes centred around too much predatory sexuality,” she says, “motherhood and her clear devotion to her children showed a different, gentler side and balanced out her reputation.”

　　The couple’s fame rose as they travelled the world with their huge “rainbow family”, alternatively making films or doing good – be it campaigning to help New Orleans after Hurricane Katrina, or working in Haiti after the 2010 earthquake.

　　Many suspect that Jolie has brilliantly manipulated her narrative so the husband-stealing/wild-child persona has been airbrushed by the human saint. Whatever the motives, for more than a decade she’s travelled frequently to some of the most insalubrious corners of the world, bringing huge publicity to previously unfashionable causes.

　　“Frankly, if a celebrity isn’t genuinely interested in poverty and is simply trying to get good press, there are better ways to do it. Travelling to Darfur or Congo is dangerous, expensive and uncomfortable, and the outhouses have bats, scorpions and camel spiders,” says Nicholas Kristof of The New York Times, who spoke with Jolie at a 2008 session at the Council on Foreign Relations about justice in Darfur.

　　While she plays the celebrity game, it always seems to serve a higher purpose than personal vanity or greed. Pictures of her newborn twins were sold for a $14 million donation to her Jolie-Pitt Foundation. Those who have worked with her say her behaviour is strikingly un-divalike and professional.

　　Still, a suspicion persists that her youthful eccentricity (her father once tearfully described her as having “serious mental problems”) has never gone away, but that her restlessness is now being channelled to positive ends.

　　Now Jolie is reinventing herself again, as a director. Her latest, second, film Unbroken, about a Second World War hero, is hotly tipped as a 2015 Oscar contender. But before picking up another golden statue, there is the matter of a visit to Buckingham Palace to collect her gong.