Pattinson’s first project since the unprecedented success of the Twilight films sees him as an angry rich kid – sans creepy vampire makeup – who falls in love with a ballsy young philosophy student, played by de Ravin. At 28 – five years Pattinson’s senior – she is still girlish enough to pass for 21.

You’ll most likely recognise the Australian actress de Ravin as the young mother Claire in Lost (currently in its explosive sixth series on Sky1), but her association with Pattinson has catapulted her into the celebrity weeklies.

When we meet in New York, where the film is set, a blizzard is raging outside the hotel window. Like Pattinson, she seems embarrassed about her success, shrugging off compliments and rolling her eyes at talk of fans and paparazzi. “I get recognised,” she says with a dismissive wave, “but I’m not the sort of person who frequents popular clubs. I try to keep out of that.”

De Ravin is part of a new breed of celebrity – like Pattinson and his Twilight co-star Kristen Stewart – who shun the glamour and adulation that many see as a perk of the job. When de Ravin slouched onto the red carpet at the London premiere of Remember Me recently, grinning awkwardly in her black Oscar de la Renta mini-dress, she and Pattinson looked as though they would rather be anywhere else.

Despite their ‘I’m-so-normal’ façade, journalists are warned not to ask about their private lives on pain of death. A hovering publicist peers up from her BlackBerry at the mere hint of a personal question to de Ravin (it could be worse: no less than three handlers accompany Pattinson during his interview). But this much we know: she married the American actor Josh Janowicz in June 2006 after being together for four years. The couple separated last year, but are rumoured to have reunited.

“Love is such an objective thing,” she says, in a suitably vague answer to a necessarily vague question about love. “I mean, I can say I love my family, or I love my Diet Coke,” she continues, gesturing towards her Coke can. “So I guess, in different ways, yeah, I do believe in love.”

But in terms of relationships?

“It’s different with every person. It depends if it… clicks. It’s chemistry.”

Either way, if she’s in love when we meet, there is no ring on her finger. Of course she was romantically linked to Pattinson during filming, but RPattz could star opposite Ellen DeGeneres and there would be rumours. Having said that, the young stars’ on-screen chemistry is undeniable. Viewers will be surprised to learn they met just one week before filming commenced.

“If you’re getting ready to do a really emotional scene then, right before it, you’re probably not going to be outside playing basketball,” she shrugs. “But everybody involved was passionate about it so there was a good vibe.”

Having not spent much time in New York before landing the role, de Ravin has now fallen in love with the city. “New York is a character in the film,” she smiles, either not noticing or not caring what a cliché that is. “It was great to be able to walk around the city on days off. And it’s so rare to be able to shoot in the real locations. When we have dinner, we were actually in The Oak Room and when we were doing a scene in the house Ally [her character] grew up in, that was in Queens.”

Of course, the downside of shooting around the city is that Twilight fans and paparazzi had easy access to locations.