With the dance, particularly, there were some days when I was just so tired halfway through. There was one time when I was in my dance class and we were like two-and-a-quarter hours in and I just have 45 minutes left, and I was like, “How am I going to get through the last 45 minutes of this lesson?” And I actually went to the toilet, sat down on the toilet with the lid down, [set] my phone alarm for five minutes and just went to sleep for like five minutes and I just woke up thinking, “Jesus, I'm not sure I'm going to be able to hack it if I can't even get through a lesson.”

You do have to get your levels of ability up to standard, but also your levels of fitness and stamina. It's been kind of beneficial to me in every area of my personal health and life, as well as just kind of being able to keep in step with Broadway.

David Thewlis’s reaction was the sweetest, I have to say. I know David and he’s a lovely guy but I don’t think in all the time that we’ve spent together we ever talked about musicals. He’s not a deep, heavy guy, but when someone’s in that film Naked you just go, “Musicals probably aren’t you’re thing.” But he just loved it. He was just over the moon, just really proud. It was really, really cool.

It didn’t cost a lot to make. It didn’t take a lot of time to make and there are only a few actors in it, but the story is so compelling. I have such faith in our director James Watkins who, as well as being a very talented man, is also very brave. I have a friend who has seen a test screening recently and there is apparently a portion for like 15 minutes in the film with no dialogue. It’s just me walking around the house, but it is apparently some of the most compelling footage. It’s going to be terrifying. At the test screening people were apparently leaping out of their seats, terrified. So I think it’s going to be a really good movie. I’m very excited. I’m very rarely excited to see stuff that I’m in – and I’m actually very excited about seeing this.

[I scare] very easily. It’s the kind of film I probably wouldn’t see unless I was in it. I know a lot of people who have said they won’t be able to see it and I’m going to have to force them to.

For me, I get very, very bored unless I’m doing something that challenges me and makes me jump through a few hoops. This is a huge year for me with the last Potter, this show as well – How to Succeed – is a huge challenge and we’re really just at the very beginning of it at the moment, then early next year The Woman in Black comes out. So the next 12 months are going to be quite telling, I think.