Awaiting the arrival of Romola Garai, I'm half expecting to see her wearing a crinoline dress and lace gloves and request we take tea in the drawing room. Which, given we're in a Berlin hotel suite, would be difficult. But such is impression this 24-year-old has left to date, with a CV that sounds like an A-Level English literature reading list. She won't thank me for this, of course. No starlet likes to be pigeonholed as a corset queen - even one who shares her first name (pronounced Rom-u-lah) with a George Eliot heroine. She positively bristles at the thought and sets out to defend herself. "I think you'd be hard pushed to think of a single British actor who hasn't beefed out their career doing adaptations of classic novels," she argues.

There's no doubt Garai has done her part for British heritage cinema. After appearing in the well-respected 2002 BBC adaptation of Eliot's Daniel Deronda, in the same year she was cast in Douglas McGrath's feature version of Charles Dickens' Nicholas Nickleby, in which she played the titular character's sister, Kate. Then there was Mira Nair's Bollywood-influenced take on William Thackery's Vanity Fair, in which she played best friend to Becky Sharp, Amelia Sedley. "I don't feel because you happen to have done a George Elliot or Dickens adaptation, you can put them under the same banner, or compare them, or say you have played the same character," she says, before realising she's been a little curt. "Sorry, I just get asked this a lot."

The problem is Garai just looks as if she's stepped out of a Victorian novel. It's all there: the alabaster skin, over-the-shoulder golden hair, cherubic features, blue eyes and full bodice-ripping figure. Sitting with her legs crossed, she keeps her back perfectly upright. Like her RP vowels, her deportment is so perfect it could be measured with a ruler. Even her dress sense - today she's wearing a short-sleeved woollen top and a navy skirt that finishes just above the knee - is inflected with period glamour. Her vintage-style cream high-heeled shoes are encrusted with beads and jewels, the sort that a princess from a bygone era might wear on her wedding day.

If Garai is the latest English rose to blossom, then this is the year we will see her in full colour. Forthcoming are roles in Amazing Grace, the story of slavery abolitionist William Wilberforce, and Kenneth Branagh's take on Shakespeare's As You Like It. Then, most significantly, she will be seen opposite Keira Knightley in the much-anticipated Ian McEwan adaptation Atonement. Although they only share one scene in the film, comparisons to Knightley, two years her junior, are inevitable. "People are always going to do that," she shrugs. "Keira is obviously much more successful than me in terms of her career. But in some ways, she has a career I aspire to follow, and so those kinds of comparisons are always flattering. So I don't mind them at all."

While she might "aspire" to the freedom of choice Knightley currently enjoys, and presumably her inflated bank balance, there's no doubt Garai has no wish to enjoy the same amount of attention. "I don't crave success in any way at all. I'm quite happy being anonymous." Admitting the thought of putting herself out into the media is "terrifying", she says she's not "emotionally and psychologically cut-out for the business side" of acting. "I don't think I'm very good at it. You should know your limitations. I'm not cut out to be one of those actors who are so successful that they've become a brand. In America, they work in a different way. An actor is more than just an actor; they're a representation of glamour and they're expected to behave in a certain way."

This is no mere conjecture. Back in 2004, Garai took the lead in Dirty Dancing: Havana Nights, the belated prequel to the 1987 Patrick Swayze classic. Co-starring Mexican hottie Diego Luna, she says she chose the film, at the time, to boost her credibility with casting directors. "I'd gone up for a couple of projects, and I hadn't got them, and part of the reason was because I didn't have any profile. I thought if I did something that was commercially successful, it would help. It sounds so sensible when I say it now. The problem was that while it is possible to be in a film that's a blockbuster and a good film, that film wasn't."

Much of the difficulty was that the script was originally just a teen dance movie set during the Cuban Revolution. "When I signed up, it wasn't called Dirty Dancing 2," she explains. "They'd bought the title and then it became this whole other thing." One swift cameo from Swayze later and it became a big deal. "It was the worst example of how you can sign up to do one film and it can become something very different," she sighs. Although she has affection for the end result - "it's like the ugly baby that nobody likes", she laughs - it's why she knows she doesn't want to be a star. "I tried it and it didn't work and it wasn't me and it made me unhappy."

Blessed with an innate innocence and pureness of heart, Garai is likeable precisely because she doesn't want to play the fame game. She has no idea how to campaign' for a role by courting a director. "I mean, what do you do? Hire planes with banners? Some actors I know will go hell-for-leather to get a role: taking the director out to lunch, writing them enthusiastic letters, inviting them to their house in France - that's buying the director, rather than purely telling them I admire you.' I just think it's dishonest. You pretend to like someone and be generous, when all the time you have an ulterior motive. I'd try to avoid doing that."

Neither is she one to be seen in the tabloids stumbling drunk out of her dress at the latest after-show party. "Not really" one for clubs any more, in truth she's a bit of a homebody and seems to spend most of her spare time in the kitchen. "I like cooking different things at different times. If you're at home on a Sunday afternoon, then there's something about baking a cake - especially if it's rainy outside. Then risotto is very calming to make. But sometimes I like doing something big and fancy, because you get to go, Da-Dah!' I cooked quail the other week" Were it not for the fact that she claims her biggest problem is getting a date, you can imagine she'd make a perfect partner.

While her networking skills leave a bit to be desired, you get the impression that if she wants to, Garai can and will outlast them all. When we meet, she is just about to start rehearsals on two plays for the Royal Shakespeare Company that are set to run concurrently from March. Both directed by Trevor Nunn, Garai will play Cordelia in King Lear and Nina in The Seagull, two rites-of-passage roles for any actress her age. "I think especially Nina," she adds. "Every young actress would always want to play her, but I'm turning 25 this year, and I'd really have been disappointed if I'd never had the chance to play this part. And not only have I got the chance to do it, but also to do it with the RSC."

While Garai has already acted Shakespeare in esteemed company, playing Celia in Branagh's forthcoming film version of As You Like It alongside the likes of Richard Briers, Adrian Lester and Janet McTeer, nothing will have prepared her for what lies in store. For the RSC, she will alternate nightly Shakespeare and Chekhov, while on matinee days, twice a week, she will perform both plays one after the other. That takes guts. "You have these two giants of writing constantly trying to impress us with what they're doing," she laughs. "It's pretty scary stuff. But I certainly think as I get older, and I've been acting for longer, I've started to feel the need to push myself and test myself in different ways."

This ability to constantly test herself is nothing new. She has recently worked for two of the most exacting auteurs in cinema. In Woody Allen's latest comedy-thriller Scoop, she plays a small role as the English friend to Scarlett Johansson's American journalism student, who becomes embroiled in a murder plot involving Hugh Jackman's aristocrat. Then came François Ozon, the French director who revitalised the career of Charlotte Rampling with the films Under The Sand and Swimming Pool. In his forthcoming film Angel, the first full-on English language movie of his career, Garai is fearless as the monstrous romantic novelist of the title. "With Angel, I could be as grotesque and ugly and real as I liked," she says with relish.

As daring a performance as she gives, there's no doubt it could have gone horribly wrong. "It's very over-the-top," she admits. "I may never work again!" But it's this ability to stand out from the crowd that makes her so compelling to watch. Take Amazing Grace, a rather drab and worthy affair in which she plays Barbara Spooner, wife to Ioan Gruffudd's anti-slavery campaigner. While little is known about her character from biographical works, Garai took it into her own hands to bring a more modern slant to the woman. "I said to director Michael Apted, Rather than make her a Regency lady in a wispy white dress, can we make her a bit earlier, and have dark colours and red hair?' Just do something a bit more striking with her and with her personality."

Having studied the period at college, Garai speaks as passionately as Spooner herself about the subject of slavery, believing the film fires a warning shot for today's audiences. "The issue of slavery is not resolved, even now," she says. "While it's not institutionalised in the same way, or controlled by governments, it obviously still goes on in huge numbers in places all over the world. And you can see yourself in Britain, with the explosion in sex trafficking going on in the last 10 years, it will always be something that people will have to fight against and hopefully that will remind people that it is possible to achieve those sorts of things."

As she speaks, Garai strikes me as an actress who needs to be mentally entwined with her roles. Take 2004's Irish drama Inside I'm Dancing, her only major contemporary film to date in which she played a care worker who becomes the object of affection for two wheelchair-bound Dubliners. "The primary school that I went to was a school set up so that both able-bodied and disabled children - mentally and physically disabled - could integrate," she explains. "That was a formative experience for me, in that my very earliest childhood memories are being at school with such a big mix. So I've known friends - children of friends of my parents - who have had disabilities. It's part of everyone's life in some way. It's just whether we or not we choose to tell the stories."

While many of her peers only seem to care about getting the latest Chloe handbag for free, Garai comes across an informed, articulate and engaged. Doubtless this wider perspective stems from the fact that she spent her first eight years abroad, living in Hong Kong and Singapore, before her family moved to Wiltshire. One of four children, Garai is the only actress. Her elder sister, Rosie, works in publishing, while her younger sister Roxanne, studied equine science. Her father Adrian is a banker and her mother, Janet, a journalist.

"What's nice, because in our family we're all good at different things, there's not a great deal of rivalry. Our parents are very laid back - there was never any pressure to succeed at anything, as long as we were happy and content." The closest there is to sibling envy, it seems, is over looks. "My little sister is the beauty in my family, so I am used to taking a back seat. She's this gorgeous, tall, skinny, Nordic-looking blonde, so I'm very used to having guys elbow me out the way."

As this suggests, Garai is not quite the English rose she might seem. Her great-grandfather, Bert Garai, was a Hungarian Jew, who eventually settled in England and founded the Keystone Press Agency. He even wrote a book about his life that Garai has dutifully read. "It's obviously not in the generation of people writing confessional autobiographies," she says. "It's very much the story of his working life, which is really interesting and lovely for me to be able to know that much about him. But he was a Jew and there's no discussion of the sense of his cultural identity or the changing face of the 20th Century at large - questions you'd really want to know about - so it's a bit frustrating."

When she was just 16, Garai left Wiltshire to live with Rosie, studying for her A-Levels at the City of London's School For Girls. It was during this time that she was cast in a small role in the TV film The Last Of The Blonde Bombshells, opposite Judi Dench, but Garai never thought of herself as an actress. While she had done school plays, and even performed in the National Youth Theatre, she had always imagined herself as a writer. Admitted to Queen Mary & Westfield college, where she studied English literature (undertaking some advanced prep for Amazing Grace), she began to take on small roles. But it was only after she was offered the co-lead in 2003's I Capture The Castle that she decided to quit university and pursue acting for good.

Based on the famous novel by Dodie Smith, in the film Garai was cast as the dowdy Cassandra, living in Thirties England with her eccentric clan headed up by a novelist-father who hadn't written a word in 12 years. Garai admits the whole experience just made her think of her own family. "My family is mad," she laughs, "and I think everybody's family is eccentric in different ways. Families by their very nature are dysfunctional. I'm lucky in that I have a very close relationship with my Dad, who really rang true to me in the film. There comes a point when daughters grow up and they're not little girls any more - and Daddy isn't the man who can fix everything. I've had to go through that with my father. We've had to come to terms with the dynamic of being two adults."

Certainly it seems Garai is making the transition to womanhood with incredible grace - even the road to stardom may be more of a bumpy ride. Set for the rest of the year to tour Australia, New Zealand and the USA with her RSC productions, she has conveniently worked it so that she should miss out on any ensuing fuss surrounding her glut of forthcoming films. At the moment, she still doesn't get recognised in the street - another advantage of playing period pieces all the time. "It never happens" she says. "But then I quite like my life, and if you're attached to the way you live, you'll be unwilling to change it." Then again, if you keep working with the likes of Ozon, Allen and Branagh, this is not going to last. Alongside that unforgettable name, sooner or later her face is going to be etched in our minds for good.

Amazing Grace opens on March 23, As You Like It is released on May 11, Atonement will open on September 14, Angel and Scoop will be released later in the year