10/02/2012 18:34 GMT

Daniel Radcliffe: Leaving Harry Potter, Growing Up, Perils Of Fame And Having A Googled Girlfriend

"Somebody said to me, 'You'll never be in a film as successful as Harry Potter.'

"I said 'You're right, but neither will anyone else.'"

Daniel Radcliffe is dealing with the inevitable questions that arise when the world's most successful child actor makes his first break for the adult film world - taking the lead role of Arthur Kipps in the creepy big screen adaptation of The Woman in Black - and, it has to be said, taking it all very much in his stride:

"I'm never going to match it, so I can forget about it now. I can always pull out some newsreel footage of the premiere. But it feels amazing to be talking about something else. Getting on set was great - I put the costume on, and I didn't have to wear glasses, it was lovely."

Even if he's obviously escaped, does Radcliffe have enough faith in audiences, Potter fans of which there are many included, to go with him?

"People may go in wondering what Harry Potter's going to do," he agrees, "but I think within the first 10 minutes, the story is so engrossing that you'll be drawn in and forget."

Because Radcliffe has been emblazoned on cinema-goers' consciousness for so long, it's hard to believe he's still only 22. He's incredibly polite, interested in other people and has a surprising self-awareness for somebody who must have inevitably lived in something of a bubble for almost half his life. How has he achieved this?

"The thing is, everyone talks about child stars like Macaulay Culkin. Nobody mentions Jodie Foster, Tobey Maguire, Elijah Wood..." he rattles off loads of well-rehearsed names of veterans like him.

"It's mainly about working hard and proving to people you're serious about it, and stretching yourself and learning. The mistake a lot of actors make, particularly young ones, is allowing themselves to feel that they're the finished articles, the bee's knees, and it's not true. If you think you are, you're f***ed."

Did that just happen - did Harry Potter just...?

He clarifies this for me: "That's to quote Alan Rickman, by the way."

Radcliffe is undoubtedly an old head on young, easily recognisable shoulders. In fact, in his manner way older than his years, he kind of reminds me of Prince William, arguably the only Brit to share the actor's experience of growing up in such a bright spotlight. He laughs at this comparison, but is more reflective on the effect it's had on his own behaviour and, more significantly, his values:

"He's had it longer than me, and I have a huge admiration for the way he handles himself, beautifully. But I've been observed for so much of my life, I don't really think about it anymore."

Even being papped through those Adrian Mole-esque growing-pain years? If Radcliffe is to be believed, self-respecting Potter fanatics have been abandoning their posts:

"I was photographed about five times in New York the whole year I was there, and that's five times more than round London," he surprises me.

"The girls have it so much harder than men in terms of paparazzi attention, but you just have to see it as funny, because it's so ridiculous.

"The fact nobody knew my girlfriend Rosie's name one day, and three days later, she was the third highest Google search result... it's not real, it's not my life, it's what people think my life is, and it's actually the reason I've started being so more open in interviews.

"I think it's useful, as a famous person, to have as little separation between the perception of you and how you really are - because otherwise I'd be sitting here thinking I'm keeping secrets, and wondering when you're going to find out."

There follows a strange interlude while I sketch out the Johari Window (a sort of psychological pie chart with public and private spheres mapped out) and ask Britain's most documented young star to point out where he sees himself. He becomes, if it were possible, even more animated during this debate:

"Fame is damaging when people become reliant on it for their sense of self, and their identity, when fame is linked to how you see yourself. Because fame is fleeting, so you're f***ed. (There he goes again, with no Rickman in sight this time.)

"The line that has made the most lasting impression on me was by William Goldman. He said something like, 'Stars come and go, only actors last.'"

So, finally, what does Daniel Radcliffe rely on then, if not the fame, the millions in the bank, the red carpet and bright bulbs? There's a big pause while he works it out, seemingly trying to be as accurate as possible:

"Good parents, good friends, immense pride in the fact that I have a really good work ethic and I love my job. My job, but not the fame that comes with it. I'd define myself as a worker and I love that.

"I know I'm not a coal miner, but I do long hours and I never complain, and there is nowhere else I'd rather be. So, yeah, that's how I'd define myself. I want to do it right, and prove people wrong once and for all about the myth of child stars."

The Woman in Black is in UK cinemas from this weekend.