I approach every part I'm asked to do and decide to do from exactly the same angle: who is this person, what does he want, how does he attempt to get it, and what happens to him when he doesn't get it, or if he does?
There's, like, marks next to an actor's name or something, and boy does that go up and down! Somewhere in there, which always causes my mate Miss Ruby Wax great hilarity, I was offered a biopic of Frank Sinatra. Even I knew that was a bad idea! They'll throw anything at you at certain times. So, you know, to thine own self be true.
When I am asked about influences, I always say I bow down to Fred Astaire, because when you look at him dancing you never look at his extremities, do you? You look at his centre. What you never see is the hours of work that went into the routines, you just see the breathtaking spirit and freedom.
Three children have become adults since a phone call with Jo Rowling, containing one small clue, persuaded me that there was more to Snape than an unchanging costume, and that even though only three of the books were out at that time, she held the entire massive but delicate narrative in the surest of hands.