It's hard to imagine anyone interested in film not being a fan of Alfred Hitchcock because he's such a key influence on the entire history of cinema - it's hard to escape his shadow.

Hitchcock is a big ask. I am playing someone significantly older than me and someone significantly bigger than me. The stuff I find very interesting is why certain physical things have come about. How can he be light on his feet when he is so big? How can his weight vary so much? Where does this rather beautiful voice come from?

When I told people I was going to be doing the movie and the voice of Dobby, they were kind of awestruck, the people who knew about Harry Potter. I felt rather guilty that I didn't really understand the scale of the job I was about to take on. Now, I am well aware of what I'm doing, and actually, it feels a very serious acting responsibility.

I often get sent scripts about little men in big situations. There's a comic element to it, which is forces stacked against this little guy, and how is he going to defeat them?

I work best when a little scared, when there's so much more than the lines to think about.

It's always very strange to have your life dramatized because it never happens like that. Things will be different.

I didn't sound anything like Capote at the screen test. It was more like Bob Dylan. In his early years. With the flu.