How different are you from Harry?
I think I am probably quite different from Harry. [But] I think we're both quite reserved in terms of how much we show our feelings. Neither of us particularly wears our heart on our sleeve. The value of friendship in both our lives is immense. And I also think we have a shared curiosity.

What do you think has been Harry's greatest misstep or failure in judgment?
Susan Bevins, you have asked a question no journalist has ever asked me. I think the way he treated his friends a couple of films ago was quite questionable. They're always there for him, and he was a little bit ungrateful. I think Harry is a flawed character. He can be quite selfish and really manipulative. He's not all sweetness and light.

The Harry Potter films have given you a chance to work with an extraordinary number of British acting royalty. Which ones have had the greatest effect on you?
The two that have had the biggest effect on me would be Gary Oldman, who I became very close to, and Imelda Staunton. They're both wonderful people and wonderful actors.

Both Half-Blood Prince and Deathly Hallows are quite different from previous installments. How have you prepared yourself for the plot's darker, deeper scenes?
To be honest, that's the kind of stuff I like doing and gravitate toward naturally. It probably comes easier to me than the comedy. On those days, I generally try to be as isolated as possible and listen to lots of music that will hopefully kind of depress me or get me into a less exuberant state.

If you could use any of the magical spells from Harry Potter, which would you choose?
It's not a spell, but if I could choose any magical thing, it would definitely be the lucky potion. If you have too much, apparently, it screws you up, but the idea of having that perfect day is just so wonderful.

Are you a Harry Potter fan?
I am a fan of the books, certainly. In terms of the films, I enjoy watching everyone but myself very, very much. I don't like watching myself. I don't think many actors do. But, yeah, I am a fan. If I weren't, I would've stopped ages ago.

What do you think about the way J.K. Rowling formed the plots of the books?
Obviously, it's inspired. Otherwise, they wouldn't have done nearly as well as they have. They have taken the best bits of different kinds of literature. It's the latest in a long line of orphan literature. There's the English boarding school. There's the good-vs.-evil thing. The fact that she came up with the entire thing on one train journey is pretty remarkable.

Would you ever commit to the lead role in a movie series again?
It would be very hard to do that in a hurry. I think it would be a while, at least, before I did that. It would have to be very good.