We're blessed with, as we were on 'Harry Potter,' lead actors who are amazingly grounded people.

I know, for a fact, that I'm a very different person on my own than I am with someone else. We are different with each other. These things are constantly adjusted. And that's true of humans. That's not just true of famous people.

I still don't feel I know Hitchcock at all. I find that the more one looks, the more elusive he becomes. But my admiration for Hitchcock the filmmaker remains undiminished. He is a giant of the cinema and the darkness in him informs his cinematic language. You can't separate one from the other.

Often jobs are un-turndownable even before you read the script. You go, "Well, I have to do that."

When working abroad you work pretty hard, but with time off, this is the greatest job in the world. You drive. You explore Memphis, or wherever you've landed, or go and see Dr John, or the Californian landscape. And, yes, I've had a few good meals.

I had to change the shape of my own voice. It was quite hard to pull off and so once I had it, I stayed in Hitchcock's voice all day on set.

I'm very interested in people, so if a character happens to be real, there's that much more to look at.