Meet Sam Mendes's British beauty: Carmen Ejogo

'I was this very precocious kid with a big personality,' she remembers. 'When my mother saw that modelling was something I enjoyed, she didn't dissuade me.' Now, Carmen seems to regret it. 'I wouldn't encourage the career I've had, starting so young,' she says. 'It's so much giving to the camera, and it's a little bit prostituting. From a very young age, I was self-conscious. My husband and I would never let our children do it,' she goes on. 'They've never even seen anything we've done.'

She was already a seasoned model when she won a role in the film Absolute Beginners in 1986, which starred David Bowie and launched the career of Patsy Kensit.

Academically, Carmen was just as much of a high-flyer, winning a scholarship to the independent girls' school Godolphin & Latymer (she was the first person from her state primary to go to an independent school), where she was in the year above Kate Beckinsale.

Shortly afterwards, her errant father died in a car crash. 'It was a defining experience,' she says. 'I was very upset, but it was surreal because I didn't really know him that well. And all this was happening when I was pubescent, a weird time in any girl's life. I became a lot more introverted, and scared of what might happen.' Her reaction seems to have been to drive herself to achieve as much as possible before fate snatched it all away. Certainly she was a girl in a hurry.

By the time she was 16, she was fronting The Carmen Ejogo Video Show on the satellite channel BSB, which was also the springboard for Chris Evans' career. 'It was a good place to begin a career, but it wasn't a career I wanted to be in,' she admits. 'It just happened because Palace Pictures who were behind it had produced the movie and they remembered me.'

Her early fame alienated her classmates. 'It's not the best environment to be coming in and saying, "I just interviewed Jason Donovan," who they were all dying to meet,' she says. 'I definitely suffered at the hands of certain girls. There was a calculated ostracism at times.'

Carmen left school at 16 when the demands of her career became too complicated to fit around her timetable. She moved on to present children's TV, first here, then on the American programme Saturday Disney.

She was making big money (she bought a flat in Ladbroke Grove when she was 20), but found herself starting to hate her profession. 'I really despised that relationship with the camera,' she says, 'and it was never where I meant to end up.' So she decided to try to make it as a serious actress. 'I wanted to work with Mike Leigh,' she says, a touch wistfully. 'I had my list of British people I wanted to work with, and I wanted to work with David Lynch and Woody Allen.'

She started well, with a role in Dennis Potter's Cold Lazarus, but then accepted a role in Metro, a forgettable Eddie Murphy action vehicle. She laughs, rather embarrassed.

'He was utterly charming but... did he tell me this? He gets told, "There's this script, it's a bit shitty, are you interested?" "No, not really." "Well, you know, we're going to give you $30 million to do it." "Yeah, all right then." And that's where he's at. He's not doing it to be the next Poitier. It is what it is for him, and that's what he's like on set. He's just showing up and getting paid, whereas I was like, "What's the motivation here?" '

The instant her scenes were in the can, Carmen fled back to London and took a role in a Michael Winterbottom film, I Want You, as a corrective to all that soulless commercialism. 'It was a completely different experience. I felt this is what I came into the business to do.'

She followed that up with The Avengers with Ralph Fiennes and Uma Thurman, in which she played a glamorous Ministry agent. At the time, she was in the throes of a four-year relationship with the actor Max Beesley, who had hit the big time playing Tom Jones in the TV series. That relationship ended in 1998.

Two years later, she met Jeffrey Wright, who was playing Martin Luther King in a TV civil rights drama called Boycott. She had been cast as his wife, Coretta Scott King. 'Actually, I didn't think I liked him to begin with. It was his energy. There was a self-confidence about him I found very frustrating and attractive at the same time. But it took my mum to make me notice. We were talking on the phone and she said, "It sounds like you might be in love with this guy." She could tell there was this turmoil going on inside me.'

The problem was that Carmen had no desire to be, as she puts it, '"The actor who falls in love with the other actor on set." So I was really resisting the feelings.' Eventually, they ended up in a passionate clinch on a research trip to Alabama. 'That was that. We've been together ever since.'

The pair seem united by many things, not least an ambivalence about the industry they work in. 'We're both highly disillusioned with the business,' she says cheerfully. 'Jeffrey doesn't really want to act any more, though he's had a much more satisfying experience than I have because he's a theatre actor. He gets to do some real work. He's interested in economic development in Africa.'

As for Carmen, the drive and ambition of her youth have, she says, more or less vanished. 'That's good and bad,' she says. 'It's bad on a day when you should be getting up and reading a script your agent has sent you and you'd rather make play-dough with your child, but it's also very healthy in terms of keeping things in perspective.'

The couple have two children, Elijah, seven, and Juno, three, and live in solid middle-class comfort in Brooklyn. They moved out of Manhattan after 9/11, and Carmen has never felt comfortable in LA. 'I just can't hack it,' she confesses. 'It's a very lonely place to be.'

Naturally, Carmen's children are having a very different childhood from her own. She seems rather to regret that, despite its deprivations. 'I really feel that I had a genuinely diverse, multicultural upbringing, and I just don't find New York to be quite as diverse,' she says. 'Maybe I'm romanticising, but I feel that I was exposed to a real melting pot in terms of culture and pop culture. My kids are essentially middle-class, but I do try to remind them that they come from humble beginnings,' she goes on. 'It actually really pains me when our son talks about "our country house".' Like it or not, Carmen Ejogo has come a long way.

Away We Go is released on 18 September 2009.

Hair by Tyler Johnston at CLM using Kiehl's stylist series. Make-up by Eli Wakamatsu at Emma Davies using Shu Uemura. Fashion assistant: Matilda Goad. Shot at The Soho Hotel, 4 Richmond Mews, W1 (020 7559 3000; firmdale.com)