I was coming from a very cerebral, dark, difficult, layered play by Christopher Hampton and doing an action movie in Hollywood (Die Hard) with explosions, and I was holding a gun.

I never talk about 'Harry Potter' because I think that would rob children of something that's private to them. I think too many things get explained, so I hate talking about it.

Acting is about giving something away, handing yourself over to whatever role you are asked to play. I'm not hiding or escaping or seeking anonymity. I reserve the right not to have a rubber stamp on my forehead saying this is who I am. Because who I am gets in the way of people looking innocently at the parts I play.

Actors are agents of change. A film, a piece of theater, a piece of music, or a book can make a difference. It can change the world.

I love perfumes. Every morning when my girlfriend and I come down to the courtyard in our block of flats we're assailed by the most delicious scent - jasmine round a doorway. It almost makes me swoon.

Nothing gives me as much pleasure as travelling. I love getting on trains and boats and planes.

I knew with Snape I was working as a double agent, as it turns out, and a very good one at that.