Q: Have you had an opportunity to consult with the author J.K. Rowling, have you met her?

One really interesting thing happened, while we were talking to her in Scotland. She's very determined that nobody shall know what's going to be in the next story until the next story is published. She has an eight year-old daughter, she was eight then, and at one point during the conversation the daughter came in, and was listening to what we were saying and suddenly said: "Mummy, what's going to happen to so and so in book number six? " And Joan looked at her very, very calmly and said: "Darling, you know I won't tell you that."

Q: What was the hardest thing for you, as a director, in this movie?

A: Oh yeah, I know what it was. The most difficult for the video stuff was under water There's a big sequence under water. What everybody who makes movies knows is that celluloid and water do not mix. They are a disastrous combination. The cameras leak, people drown, people get cold, it's a disaster. Do not get near the water with a film camera. So we were desperate not to shoot the underwater sequence in the water.

So what we tried to do first was to shoot the whole thing upside down in dry land, which meant that we had to have a system of blue scaffolding poles, because the computer can take out blue. We would then hang the actors off the poles, upside down, because their hair would hang down like their hair would hang in he water. So of course the problem with that was that everybody went scarlet in the face, terrible, complete fiasco. So what we had to do then was train all the actors to swim like fishes and shoot it in this huge tank. But then the computers put in everything. They put in the fish, they put in the weeds, they put in the little dots in the water, everything was done with the computer, quite brilliant.