Rhona Mitra, innit

Rhona Mitra has forgotten the name of her character in the new Ali G film.

'Oh my God,' she wails, legs swung casually over the arm of a wicker chair in LA's illustrious Chateau Marmont Hotel on Sunset Boulevard. 'I can't remember her bloody name. Oh, isn't that awful, I don't believe it.'

Only moments before, the British actress had been boasting, in a posh drawl, about bagging the coveted role. 'So, I got the director on the phone and I said, "Look, I don't care how, who, what, where, when. I need to do whatever it is and I'll do it now. Sacha Baron Cohen is a genius and I want to be a part of this project."' Strange, then, after so much effort to get the part, she can't remember her character's name. 'I know, but it was a year ago,' she sighs, still clutching her forehead in mock horror.

Mitra does, however, remember the sort of woman she plays in Ali G Inda House. Her character is, she says, an 'evil bitch' who works for the 'baddies'. 'She's also posh, pretty totty, educated at Oxford and now working for the government - a woman who knows how to use her vices.' So does she get to bed our hero from Staines? 'No, but not for lack of trying,' she smiles coyly.

In Britain, 25-year-old Mitra was famous for being the scantily clad human form of Lara Croft, star of the bestselling Tomb Raider computer games. She got to pose at lots of trade fairs, appear on the front of FHM and become the favourite pin-up of the joystick generation (a search under her name on the internet pulls up 11,000 matches). Today, perhaps deliberately, her curvaceous body and cosmetically enhanced bosom are hidden under baggy, navy slacks and a white, chunky, knee-length cardigan. As her choice of outfit implies, she wants to be taken more seriously.

She quickly takes control of the interview, ordering mineral water and asking my opinion of LA, while I adjust my tape recorder. The easy confidence slips, however, when I ask if she enjoyed working with Baron Cohen. Her personality, like her accent, is a curious mix of British and American - one minute polite and self-effacing, the next brash and self-assured.

'He really wasn't what I was expecting at all,' she begins hesitantly, biting her lip, before starting on a confused ramble. 'What's in his head and what you try to put out there are two totally different things.' From this, I interpret she couldn't always translate what Baron Cohen required of her. 'He'll suddenly get a whiff of something else, go off on a tangent and then everything will be changed.

'Sasha is f***ing funny, though,' she continues, all smiles again. 'It was hard keeping a straight face.' As well as starring in the film, Baron Cohen wrote the script while Steve Bendelack directed. 'Sacha was still very hands on,' she recalls. 'I mean, it's all him. No one else can get inside his head.'

As she wasn't able to catch The 11 O'Clock Show nor The Ali G Show in the States, Mitra first watched the 'voice of yoof' in action over Christmas 2000. 'My brother, Jason, sat me down and said, "Watch this."' She grins impishly. 'I peed my pants.' The film will be released in America later this year. Although success in Britain is virtually guaranteed, Mitra thinks America might be harder to crack. 'There are people on the East Coast who know who Ali G is, but here you have to say, "the guy who drives the limousine in the Madonna video". So I doubt it will make a huge difference to my career. Not that I did it for that reason,' she adds hastily.

Mitra's own teenage years could be worthy of a film script: 'Prominent surgeon's daughter is thrown out of two posh boarding schools (St Mary's, Shaftesbury, and Roedean, Brighton), heads to London's clubland aged 15 and inevitably takes drugs. Three years later she has a moment of clarity, upgrades to a 34D chest, gains entry to respected London drama college only to quit a year later.' 'I was always known as "that girl",' she sighs. 'I hate being confined by four walls, getting judged by other people. I thought I was better off out and about causing trouble.'

She is less relaxed when conversation turns to her father, Anthony Mitra, a cosmetic surgeon (contrary to rumour, he did not perform her breast enlargement). He split from her Irish mother, Nora, when Rhona was six. 'I don't see much of him, that's all,' she replies evasively. 'My mum and two brothers are my best friends.'

Her first major role was Flora, the schoolgirl temptress in the TV adaptation of Jilly Cooper's The Man Who Made Husbands Jealous. Then a couple of small film roles, including Beowulf with Christopher Lambert. Her relationship with the French sex symbol didn't get off to a great start. 'I got drunk on the first night and vomited all over him,' she laughs. Lara Croft was the last job before she moved to LA. Within two weeks of arriving she was offered two roles, one of which was for a season in the TV teen drama, Party of Five. 'So I went home, packed up in ten days and moved out.'