What other people think of me is none of my business.

I grew up in Deptford in south London, and at that time I used to wear toppers, loon pants and tonic suits from shops like Take 6 and Topman. I was a bit of a soul boy, but I had a very eclectic taste in music - I was into James Brown and Bowie; and I was the only kid in the neighbourhood who would also be listening to Chopin.

And of course I've got kids of my own now, and they love me being in the Harry Potter films. I'm now part of a phenomenon. You become incredibly cool to your kids, and you get a young fan base. So you became the cool dad at school. You're suddenly hip.

People have an idea that one is in control of a career, a lot more than you really are. You can engineer things to an extent. But you are at the mercy of what comes in across the desk.

When you play a character that is so emotionally closed there are times when you ask yourself if you are doing enough and if it's reading. That is where you have a director, who is the barometer of what you are doing.

Impressionists have to paint with a very broad stroke because you've got to see it within a couple of seconds. You go, "That's a really funny Robert De Niro." As an actor, though, you look at different aspects of a character. I try to completely surround myself with the assignment. It's like being in a big cloud and then some of it rains through.

Political correctness has become a straightjacket.