Paint the town Scarlett

Lolling about on a squashy hotel sofa, clad in zip-up flying boots and a rose-pink off-the-shoulder top, Johansson is so physically tiny, she appears to be occupying one of those outsize pieces of furniture that impressionists use when they're doing Ronnie Corbett. She greets me with an apology. 'This room smells of cigarettes and curry,' she says, flapping at the air with a languid hand. 'Sorry about that.'

She was born in New York in 1984, the daughter of a Danish architect. She has a twin brother called Hunter. ('He's six-three and olive-skinned. We don't even look related. People think we're dating. It's disgusting.') She pestered her parents into enrolling her at the Lee Strasberg Theatre Institute at seven, made her first off-Broadway appearance at eight, opposite Ethan Hawke, and since then she's appeared as a tragic one-legged teen equestrian in The Horse Whisperer, Thora Birch's glacial co-conspirator in Ghost World, and the sweet young thing who fellated Billy Bob Thornton into a road accident in The Man Who Wasn't There. She's spent the past 12 months - her gap-year between high school and film school - shooting with Bill Murray, John Travolta, Dennis Quaid and Helen Hunt.

In deference to her heritage, she ought to sound the initial letter of her surname with a soft J - as in, say, Jorvik Viking Centre. But she says Johansson like Joe Bloggs - and she does it in a deep, languorous rasp that's unusual in a 19-year-old. It might be nature, it might be the cigarettes, it might be the result of studying Lauren Bacall in The Big Sleep. But you won't hear much of it in Girl With A Pearl Earring. As the maidservant immortalised in Vermeer's portrait, Johansson manages to become the object of the film's attention with just a handful of lines. 'It's a lot easier if you don't have to deal with fumbly dialogue,' she reflects. 'I'd much rather not say anything at all than say something cheesy.' She imagines the worst. 'Oh Vermeer,' she smoulders. 'Your long locks are sooo dashing!'

In Lost In Translation, Johansson and Bill Murray play two lost souls who hook up in an anonymous Tokyo hotel. She's the disappointed wife of a shallow photographer, he's a faded movie star whoring his way through a Japanese whisky commercial. As they pursue a halting, inter-generational courtship, the hotel plays host to a press junket for an impossibly stupid action movie. Johansson seems cross and baffled, however, when I suggest the film reads as a cautionary tale about the uncertain nature of a Hollywood movie career. 'Is it?' she demands. 'Is it that bad? What's wrong with selling whisky or shampoo overseas? You're not selling out. You're selling shampoo. You make so much money doing something like that and, who cares? It's the same as getting a cosmetics campaign. You're selling your celebrity in the same way that you'd promote a charity. If it's offered, that kind of thing is really appealing.'

She's much more discriminating about movies. 'After I did Horse Whisperer,' she explains, 'I had no reason to settle for a gross comedy or teen slayer movie. I didn't feel the need to settle for anything that would be a total embarrassment. Not that it's not fun to shoot that kind of thing. It's just that you've got to promote it and there's nothing worse than promoting a movie you've got nothing to say about. So I just stayed in school.'

And what was the most embarrassing script that curled on to her doormat? 'Oh my God,' she drawls. 'I've been offered so many stupid things.' As she attempts to recollect what they were, Johansson rolls around, lying on her back, until she looks as if she's at a session with her shrink. 'Scripts about young girls getting pregnant when they're 14,' she says. 'And the ordeal they go through trying to hide the pregnancy. Or things in which my character is very visibly and grotesquely raped and cut into little pieces. I never had any reason to take stuff like that. I'm fortunate that I didn't have a psycho stage-mom pushing me into things.'

Ironically, the discernment she's shown so far might ensure her a better chance than most at the live-forever, learn-how-to-fly kind of fame. 'In 80 years time,' she asserts, 'I hope to be one of those old people who staggers on to the stage at the Academy Awards. And I want to be able to be a really bad driver and rear-end people without anybody saying anything.' Could she cope, I wonder, if in 80 years time everybody had forgotten who she was? 'I don't want to be forgotten,' she says, appalled at the thought. 'I want to be a celebrated old hag.'