I was in the bath at the time, and my dad came running in and said, 'Guess who they want to play Harry Potter!?' and I started to cry. It was probably the best moment of my life.

I would say I was challenging the system quite. But I like to think that if the choices I make are slightly unexpected or challenging to people, then that is good. We are definitely three fairly like-minded people in terms of what we value in scripts and in storytelling.

And the people I'm best friends with on the films are not generally the actors.

Because I'm short and slim, I can identify with somebody who's an unlikely fit for something and desperately wants to be part of it.

I don't think that you necessarily need a certain type of background to take on roles. You see actors from very, very privileged backgrounds playing working class characters and vice-versa. I don't think your background limits you as to what you can do.

I'm also a fan of ridiculously coloured and patterned socks.

I thought I was an actor playing a wizard. But really, I was a wizard playing an actor.