Daniel Radcliffe's tastes have changed. Gone is the can of Coke that accompanied him into Potter-era interviews, replaced instead by a white coffee in a delicate china cup.

He's still as charming and blissfully candid as he ever was, but his words seem more considered and his enthusiasm, while boundless, is no longer quite so puppyish.

In short, he's now a man. And one who's determined to show the world what he's capable of after a decade of playing one of fiction's most famous heroes.

Fresh from an acclaimed stint on Broadway in the all-singing, all-dancing How To Succeed In Business Without Really Trying, the next weapon in his arsenal is the film adaptation of gothic thriller The Woman In Black.

"This is the first step, absolutely, in the transition of me moving on and doing other things – and it's one I'm very proud of," he says, earnestly.

"People are going to stop thinking about Harry Potter pretty quickly when they see this film. Even if they go in thinking, 'What's Harry's up to now?', the story is so compelling that after the first five minutes, 95 per cent will not be thinking that."

Based on the classic 1983 novel by Susan Hill, which was adapted into the successful West End play, The Woman In Black has been slightly reworked for the cinema by Kick-Ass writer Jane Goldman.

Radcliffe plays young London solicitor Arthur Kipps, who lost his wife when she was giving birth to his son.

Eager to please his boss and keep his job, he leaves the boy and travels to a remote northern village to wrap up the affairs of the deceased owner of Eel Marsh House. And that's when the spooky sightings of a mysterious ghostly figure begin.

The 22-year-old actor's own godson, Misha Handley, plays his son, which Radcliffe says made his transition from young man to father more convincing.

"I knew it might be a hindrance to making me seem older if the relationship with my son didn't feel real. They auditioned a lot of boys for that part, but it was very hard to beat that natural chemistry, because he's known me all his life," he says.

But playing a father wasn't the hardest challenge Radcliffe faced. While Harry Potter and he shared a similar vigour, the character of Arthur was a totally different animal.

"My energy levels are naturally very frenetic and Arthur is somebody who's been completely deadened to the world; stripped of his own vitality and zeal by the tragic circumstances of his wife's death. He's totally detached from other people."

And then there was the scene with all the mud, when Arthur dives into the marsh to try and recover a body.

Radcliffe spent three days in a cold tank of "Saturday morning children's show" gunk. "I thought it was going to be really cool, I was getting all psyched up to break the surface like Apocalypse Now, but when I came up, I was informed I looked more like Al Jolson."