What was the most challenging thing to film physically [in Deathly Hallows - Part 2]?
Dan:The stuff actually in Gringott’s bank in the Lestrange vault where all the treasure is multiplying and multiplying, that was very hard. The way we did it was we had moving platforms on the set so that as the treasure multiplied, these platforms would move up and I would have to struggle onto the next one and then onto the next one and then on to the next one. I don’t think my calf muscles have ever worked quite so hard. So that was, physically, a pretty challenging thing.

What as it like to film the scene with Helena Bonham Carter playing Hermione as Bellatrix?
Dan: It was very, very funny. It was actually one of my favorite scenes on the film to do was all fo us, Warwick Davis, Helena and Rupert all on the cart going into Gringott’s bank. Of course Helena and Warwick are hysterically funny, both of them. I basically became Helena Bonham Carter’s PA on this film. The first day I was going, “Helena, you gonna hold that coffee? Do you want that coffee in this shot or do you want me to move it somewhere else for you? Are you gonna use that character thing you’re doing now?” She’s mad and brilliant and wonderful and everything I love about the English people. So that was great fun. The scene then when she whips the dragon’s back was also hilarious. On that part me and Rupert were all soaking wet. It was great fun. It was very, very funny. Helena as Hermione is very, very funny. Or rather Hermione as Helena … it felt very confusing.

Did she have to be a little bit more conservative?
Dan: Yes, yes. Yes, she certainly did than she would normally be as Bellatrix.

Part 1 is more of a road movie. Was it a really different experience playing Harry?
Dan: Absolutely. It’s a very different film. It’s bizarre, in a way. I don’t think we were aware how different it was at the time of filming. At the time we were just doing scenes like we’d do any other scenes. We weren’t really thinking about how different it was going to eventually seem. But then when I saw the trailer and saw the extra footage I’ve seen, it just struck me how very different it’s going to be because we’ve never seen these characters in this different context before. I think it’s one of the things that makes the first film so exciting. You see these characters stripped of their comfortable safe surroundings, and suddenly just out in the wilderness together. The first one, as well as being that road movie, because they’re all overexposed and it’s such a different situation, you learn a lot more about how those characters function in that situation. It’s a real exploration of the relationships between them and the flaws – particularly Harry and Ron, because Hermione as always is the voice of reason. But Harry and Ron do fall apart to some degree. It’s a very different feel to it.

Can you talk a bit about the final battle and the emotion [since] Harry’s gone away and comes back to find everyone fighting and Hogwarts on fire?
Dan: It’s a bizarre thing. It wasn’t so much the courtyard scene in the battle that was emotional, it was actually seeing the Great Hall destroyed and turned into a field hospital, which was the slightly more emotionally shocking moments. The Great Hall is such an iconic set. Seeing it destroyed is bizarre. The emotions for us all were that really brought home the fact things were coming to a close. Sad as that was, it gave us an awareness of how much it mattered that we get this right. How much we owe it to all the people who have supported us for so long to get it right, as well as for ourselves. It’s a huge motivation because we’ve been there for ten years and don’t want to go out in any other way than spectacularly. Also to the people who have watched for so long, we know we owe it to them, as well, to make this film the best we can.

What was your favorite thing in the movie and why?
Dan: There’s so many to choose from. And the truth is, this year, we filmed this film over a period of 17 months, so I’ve forgotten a lot of it from the beginning. Here’s actually one of the two favorite scenes. One of them is when I’m going into the forest. I see the ghosts of my parents and of Sirius and Lupin. They’ve come back to give me guidance and comfort in what are, in theory, the last moments of Harry’s life. I’ve always found that scene right from when I read it in the book to be one of the most moving moments in all the films. And also, on a personal note, I had missed having Michael Gambon on set very, very much. And so to do the Kings Cross scene where we meet in this half life, limbo world was also one of my favorites because it’s an amazing set. It’s slightly odd, disturbing, more surreal than Harry Potter’s ever been before. So that would’ve been my favorite scene probably.