Rachel Weisz: The constant star

She's sexy and smart, with a Golden Globe on the mantelpiece. Will an Oscar follow?

It was while she was polishing her Golden Globe award for Best Supporting Actress in The Constant Gardener last week that Rachel Weisz heard she had been nominated in the Best Actress category for the same film by Bafta. The role provided an opportunity for her to play an expectant mother: how apt then that last week also brought confirmation that the 34-year-old actress is five months pregnant, by her fiancé, Darren Aronofsky, the maverick American film director.

Not bad for a former rebel teenager who spent five years in therapy. As a British actress with some serious stage time in the West End, she looked like being the first actress to inherit the mantle of Helen Mirren, the thinking man's nymph.

But Weisz had an early determination not to be confined to the stage. Turned down for an American mini-series because the executive producer said she had "an overbite", she had a hesitant start in movies with a one-line debut in the justly forgotten Death Machine (1995). One year later, in Stealing Beauty - Bernardo Bertolucci's louche study of a dying artist - Weisz found a way to dominate the screen. She played sexy.

It is an act, say her detractors, that she has been repeating ever since. Her screen persona often exhibits a marriage of sharp intellect and uninhibited carnality. Irresistible to some, irritating to others, it has never been more perfectly illustrated than in her performance as Tessa Quayle in The Constant Gardener.

She was born in north London on 7 March 1971 into a brilliant but competitive family. Her parents arrived in Britain just before the outbreak of the Second World War to escape the imminent Holocaust. Her father, George, was a Hungarian inventor responsible for some ground-breaking medical devices; her mother, Edith, was a Viennese psychoanalyst. Weisz soon discovered that the best way to unite her warring parents was to become rebellious. Consequently, she was expelled from a series of schools, including North London Collegiate and Benenden, for "disruptive behaviour". At the age of 13, while at St Paul's Girls School in London, she was carted off to a child psychiatrist. She later received a letter from her shrink which read: "Congratulations. You are doing very well at keeping your parents together." Sadly, not well enough. By the time she was 15, they had separated.

While Edith, a putative actress, encouraged Rachel to enter the profession, her father discouraged it. But Weisz was modelling at 14 and was offered a part in King David, starring Richard Gere. Her decision to turn it down seems to have polarised her parents.

But the die was cast and at 17 Weisz knew she wanted to act. Acquiescing to her parents' demand to finish her education first, she spent a summer studying with the theatrical maverick Ken Campbell before going up to Cambridge to study English. She obtained an upper second and the heart of student Ben Miller - later co-star of Armstrong and Miller comedy show - with whom she lived for four years.

The student productions in which she involved herself revealed a taste for the unorthodox. She appeared in Howard Brenton's The Romans in Britain and Lorca's Blood Wedding, and co-founded Talking Tongues, an improvisational theatre group that brought her to the Edinburgh Fringe. There she won a Guardian award for a violent, hugely physical piece of theatre called Slight Possession, in which she and fellow actress Sacha Hails threw each other around the stage and off a stepladder.

It impressed director Sean Mathias enough to cast her in his 1994 production of Design For Living, which really got her going. Her vividly sexy performance won her the London Critics' Circle Award for Most Promising Newcomer, and she became a poster girl for male theatregoers. Success in theatre and on TV notwithstanding, this was an unhappy time for her; she has described her work in this period as "Crap and more crap. I was crap, it was crap." Such self-criticism led to a lengthy time in therapy against the express wishes of her mother, who ought to have known what she was talking about.

When Hollywood crooked a gilded finger, she willingly followed. Even in second-rate pictures it was clear she could hold the screen against her A-list male stars, whether as action arm candy for Keanu Reeves in Chain Reaction and sassily confident against a comically lecherous Dustin Hoffman in Confidence.

"She is too clever not to be aware of the ironies of showbusiness and its inherent silliness," says the columnist Matthew Norman, who tutored the 15-year-old Weisz in Latin. "If anyone's going to win an Oscar and not flirt with being a diva, it's Rachel. She's got far too developed a sense of irony for that. She's fearsomely bright. It's not in her nature to be troublesome. She is very un-actressy."

To maintain a sense of proportion, she returned to the stage in Britain - gathering wow notices for Neil LaBute's The Shape of Things although she was unable to recapture the performance in the screen version.

"As an actress she has the ability to be so committed to what she does," says Susan Lynch, with whom Weisz starred in Beautiful Creatures. "But at the same time [she can] put it all into a healthy perspective." Perhaps her greatest asset is her sense of humour. Her feel for comedy emerged in The Mummy and its sequel, in which she appeared as a ditzy librarian who transforms herself into an all-action Lara Croft-style Egyptologist. As a result, Playboy offered her a centrefold shoot. She turned it down.

Her love life has been well documented, mainly because of the high profile of her boyfriends, and has bestowed upon her a celebrity status that she neither desired nor appreciated. She dated Neil Morrissey after appearing with him in My Summer with Des, and then Sam Mendes, the Donmar theatre supremo-turned-film director. She appears to have met her equal in Aronofsky, whose films Pi and Requiem for a Dream are prime examples of cutting-edge, US independent movies with big brains. Having set up home in New York four years ago, they worked together on his forthcoming science fiction epic, The Fountain.

So Weisz is on a high. She's earned her acting chops through hard work; enjoys the rewards, including a contract with Revlon cosmetics; and now, with Aronofsky and an imminent child, she has exorcised the family demons that dogged her youth. "I found myself a sophisticated, educated American," she said recently. "He's not an actor. He's travelled the world. He knows where Europe is, unlike a lot of Americans. He's very cultured, but he's all man." He'll need to be.