Wearing jeans, a white shirt and jacket, he’s looking pretty tired and dishevelled but there’s no denying his wide-eyed good looks, even if he is trying to hide his chiselled features underneath stubble.

He and his co-stars are currently on a world-wide promotional tour of New Moon, and the relentless schedule means he only has a few hours in London before the Twilight carnival continues to another country. “It’s so funny being close to home and the same thing happens,” he says of the screaming fans. “I always thought it was a foreign thing.”

If he looks and sounds a little bewildered and embarrassed by the reaction, he explains: “I’ve been working for most of the year, so I’ve been kind of insulated from everything while it’s been exploding around me.”

Even though his new-found fame has forced him into spending most of his time in hotel rooms, you don’t hear Pattinson complaining, although he’s admitted he isn’t “really a crowd person”.

“It’s such a novelty to me still,” he says pushing his hand through messy hair. “If I’m still stuck in hotel rooms in ten years and I haven’t figured out any other way other than hiding, it probably would annoy me a little bit.”

Aside from anonymity, he says there are only a few things he’s had to give up since Twilight hysteria took hold. “But I never did much in the first place,” he adds with a smile. “When you’re working, you’re just waking up at 5.30am, going home too tired to do anything and you just want to go to bed.”

An accomplished musician, he does miss playing the piano and guitar at open mic nights, something he used to do when work dried up pre-Twilight. “I guess the only way to do gigs now is to do an album to silence everybody first. Then you can play as many gigs as you want.”

Pattinson’s first foray into acting came care of the local Barnes Theatre Club where he took part in a production of Tess of the d’Urbervilles. His performance landed him an agent and a role in Vanity Fair, a part that ended up on the cutting room floor. Apparently, the casting agent felt so bad for not telling him what had happened, she put him forward for the role of the doomed golden-boy Cedric Diggory in Harry Potter And The Goblet Of Fire – a role he won. “When I went into Harry Potter, it was the fourth one, so everybody knew each other and everything was so well oiled,” says Pattinson.

“With Twilight, it was very weird doing a franchise at an embryonic level and interesting to see so many warring energies.”

According to director Catherine Hardwicke, Pattinson had to get up and leave a third of the way through the first screening of Twilight, because he couldn’t stand watching himself. “This one’s easier,” he says, rubbing his neck. “I’m kind of a supporting role. Taylor (Lautner, who plays werewolf Jacob Black) is the soul of the movie.“

To satisfy the teenage thirst for the boys and their pecs, “You get a lot of nipple shots in this movie,” says Pattinson, laughing. Lautner piled on 30 pounds of muscle for the second movie and it’s his physical transformation that’s currently causing a stir. “I was really terrified,” says Pattinson, chuckling. “I hadn’t worked out at all and then I saw Taylor at the beginning of the year and I did feel incredibly inadequate.”

Bewildered, almost apologetic about his success, it sounds like he has his family to thank for keeping him so grounded despite the hype. “I don’t think they really know what I’m doing,” he says with another infectious chuckle. “I still think they have trouble understanding I’m supposed to be an actor, the same way I do.”