Rachel Hurd-Wood is a knockout. Tall and slim, with proper curves, a halo of strawberry blonde curls, creamy skin, huge periwinkle blue eyes and a neat tip-tilted nose, she's a perfect English rose. No wonder she's well on her way to proving herself the next Great British Film Talent.

But behind her angelic looks, the 19-year-old reveals a dark side: no romcoms for her; Rachel's favourite films are twisted - Pan's Labyrinth, The Orphanage, Carrie. Jeff Buckley is her musician of choice, and forget Sleeping Beauty, her best-loved fairy tale is called The Stringla Princess, 'about this girl who cuts and kills horses and stuff and then she cuts all the limbs off her family and her brother runs away and she eats him,' she explains with a shrug.

Other than her breakthrough role, aged 12, as Wendy in PJ Hogan's blockbuster version of Peter Pan, she has always chosen to play tormented ingénues.

In An American Haunting in 2005 she took on two characters, the victims of violent hauntings (in a neat twist, Carrie star Sissy Spacek played her mother); in Perfume: the Story of a Murderer, the 2006 adaptation of Patrick Süskind's bestselling novel, she was stalked by a murderous Ben Whishaw, obsessed by her smell; in Solomon Kane, a comic-book adaptation set in 17th-century England, out later this year, she stars alongside James Purefoy and Pete Postlethwaite as a Puritan girl enslaved by demons from hell; and in the film she is here to promote, Dorian Gray, she is driven to suicide by her fiancé, the heartless hedonist Gray, played by Ben Barnes (Narnia's Prince Caspian).

They can't be easy roles to play, and she manages to bring vitality and feistiness to her performances that ensure no character of hers is ever simply a victim. 'I'm not dark, I'm not,' Rachel insists, a picture of wide-eyed innocence.

'The main thing I consider in accepting a role is less the tone of the movie and more whether I think it's a good film, whether I like the character and whether I think I could do it. I don't think, "Oh, I've done X amount of dark films." '

She likes lighter things, too, she goes on, like dolphins (she wanted to be a marine biologist as a child, until she found out you needed to be good at science) and Beyoncé and drawing. In the end, I put the dark side down to insouciance; it's not so much that she's obsessed by the darker side of life as that she isn't fazed by it.

(Left) Rachel wears one-shoulder dress with tie belt, £685, Moschino at Harvey Nichols (020 7235 5000)

Maybe it is for this that directors have been drawn to her for tricky roles, rather than the other way round. As Dorian Gray director Oliver Parker says: 'Rachel has a genuine openness as an actress and a person. There is real strength in her innocence.' Perfume director Tom Tykwer called her 'an old soul in a young body'.

It's a good description. Rachel is a curious mixture of teenager - upbeat and chatty, her conversation enthusiastic and filled with superlatives - and pragmatic movie-set oldtimer. She takes a deep breath when I ask if filming scary scenes is ever actually scary, eyeing me with a mixture of pity and longsuffering goodwill over her bowl of quinoa salad. 'Not really. You're acting, aren't you? Pretending to be scared.' She pauses, allowing time for this information sink in, then decides to throw a bone in kindness, 'Well, sometimes they do stuff to make you jump; to get a reaction.'

She was born and raised near Guildford. Her father works in PR and does voiceover work on the side, her mother is a housewife and her younger brother, Patrick, is 'unlike me, really good at music'. (She is far quicker to point out all the things she isn't good at: music, sport, theatre - 'I'm useless at it; getting on stage in front of a bunch of people is terrifying' - than to admit to any talent in front of the camera.

She has just completed the first year of a linguistics degree at UCL and it's in language she says that her passion truly lies. 'I wouldn't be upset if I never acted again,' she announces. 'I've had an amazing time so far so I'm not regretful, and obviously if there are more roles coming then I'd love to do them, but if not then I'll teach, so it's fine.'

(Right) Rachel in Dorian Gray

Parker thinks this gives her strength. 'She has quite a career ahead of her if she wants it,' he says, 'though I'm not convinced she does, which may be one of the reasons she's so good.' She's interested in teaching young children, possibly speech therapy. 'As a kid at school, I had a lot of really good teachers and I had a lot of really bad teachers and I just know how much of an impact those can have on a young child. To be one of the good teachers, I want to have that kind of impact.'

She is clearly very bright but, naturally, dismisses it. 'I'm not like a bloody genius but I did all right,' she says of her school days at Godalming College. 'I'm not thick.' She's not interested in her own burgeoning celebrity. 'I'm uncomfortable with the limelight. I'm not the type to go to the places where I know I'll be seen. I'd rather keep a low profile.'

Instead she enjoys making an impact on screen. She loves the process of film-making and filming Dorian Gray was, she says, 'brilliant', in spite of having to face her first sex scene, with Ben Barnes. 'That was day one. It was very surreal. I couldn't not laugh. It's eight on a Monday morning and I'm snogging this bloke I don't know.' She's seen the film once and reports that 'the sex bit wasn't too bad actually. It's pretty mild. I was all right, I suppose, and the film's really good so that's OK.'

It has an amazing cast, I say (Colin Firth, Fiona Shaw and Rebecca Hall co-star). She agrees. Did they give her any tips? Another shrug, nonchalant as ever. 'I didn't really ask.' Indifference? Shyness? She may not be sure she wants it, she may not be trying very hard for it, but this young bombshell is quietly shrugging her way to stardom.

Dorian Gray opens on 9 September 2009

Hair by Juan Carlos at One Make-up using L'Oréal Professionnel. Make-up by Carol Morley at One Make-up using Nars. Fashion assistant: Matilda Goad. Shot on location at Fulham Palace, SW6 (020 7736 8140; fulhampalace.org)