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.

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.

Definitely a change from “Order of the Phoenix,” which was a thriller, really. It had a lot of action.
NH: Yes, “Phoenix” was quite a new thing for me in that sense. I had scored action in films before, but to do it on that scale was really something.

“Half-Blood Prince” is arguably the darkest of the books. How’d you get into the right frame of mind? [His answer has spoilers if you have not read the book!]
NH: We started working on a piece that was going to come towards the end of the film, right before Dumbledore is killed. It was a somber piece for a choir and drums. Of course, the sequence was dropped from the film, but it had in it the seeds of the germ of the idea that actually follows Dumbledore’s progress throughout the film and comes to quite a musical height at the point where Harry and Dumbledore travel to find Voldemort’s secret Horcrux in the cave. It’s a big moment.

The other major piece of inspiration came from “Order of the Phoenix,” the possession theme that plays at the end of the film when Voldemort possesses Harry and Harry manages to reject and repel him through love. That piece of music also works its way through “Half-Blood Prince” coming to quite a height at the point right before Dumbledore dies. Those two themes play quite a big part in this film, which is all around a much more emotional film, I think, than any of the others. It’s much more about relationships. The relationship between Harry and Dumbledore, the boy-girl stuff going on. I think everyone is given a bit more depth in that sense. The music reflects that.

Can you elaborate on what the idea was behind the original choir-and-drums piece you first wrote? [Again, spoilers if you haven't read the book.]
NH: David wanted to film this school choir, the Hogwarts school choir, having a choir practice when all this evil stuff at the end of the film was going on in the background. It would have played during an interim moment -- after the events in the cave and before the Death Eaters arrival at Hogwarts. Originally, there was this gap and the idea was that it should be this build-up for Draco to Dumbledore’s death. It had almost a Garden of Gethsemane feel to it. But eventually, the thinking became that injecting scenes with a choir would have held up the climax. Now, the film glides straightaway from the cave to the end, which I think was the right decision. The music itself, however, can still be heard during the credits of the film, and it’s also on the soundtrack.

Draco plays a major part in this film – does he have his own theme as well?
NH: He does. It follows him throughout all his visits to the room of requirements. Definitely a Malfoy theme, yeah. It’s an odd mixture of dark and sad. Well, not sad exactly. It’s moving though. Here’s this poor boy who has been kind of pulled into this. You don’t just feel he’s really evil. So the music couldn’t be about his being evil. It’s not about that. It’s about this kid being pulled out of his depth, really.

Do you have any favorite pieces from this film?
NH: I think my favorite moment was Harry and Dumbledore in the cave because it’s just so big and tough. A couple of people came to listen to it when I was finished and they were in tears after they heard the recording and I thought, “Oh, that’s nice.” I feel like I moved people. I have to say the Harry and Ginny moment is another favorite.

It’s different than in the book, though, isn’t it? [More spoilers!]
NH: It’s all kind of strange. They’re in the room of requirements and they’re trying to hide something and they even come across Malfoy’s secret and they don’t know it. Then they kiss. It’s a lovely, beautiful moment in the film. It comes out of an earlier moment when Harry sees Ginny at the beginning of the film. It’s not music that reoccurs throughout the film. It’s just one special melody in the middle.