The LA Times has posted an interview with composer Nicholas Hooper.

DM: You’ve known and worked with David Yates for the last 19 years. How did you feel about taking on a project as big and well-known as the “Harry Potter” movies?
NH: I was already a fan of Harry Potter from the books. When the first films came out I had to go watch them, of course, and I thought I’d love to do one. Then David told me he was going to do one and I nearly fell over backwards because I didn’t expect it at all. David had done political thrillers and those kinds of things, so this was something quite different.

DM: How were you able to put your own stamp on the score when four movies had already been done with a more or less established sound?
NH: I started by listening to a lot of the John Williams score, particularly from the third movie, “Prisoner of Azkaban,” which I loved and I suppose is closest to what I was trying to do. I used some of his themes, particularly his Hedwig theme. After that, we all decided that it was best if I moved into my own way of composing rather than trying to emulate John Williams, which is impossible. I did a different kind of score for “Half-Blood Prince,” really. It was simpler, the way I write music is simpler.