I think you only watch stuff you've done once because I don't think it's that beneficial to you. I think it's important to sometimes be like, 'What's that thing I'm doing with my face? I didn't think I was doing that.'

It's funny when you know you're playing two characters and you're aware of how you have to play each one into your performance of the other. You're constantly at the back of your mind thinking and it all gets a bit confusing.

I was and still am a massive fan of [Murphy] Cillian's work - always have been. Obviously he's a great deal older than me, so I've sort of grew up watching Cillian's work. But I'm very much a fan.

That tag - underwear model - I just can't get rid of it. And it's such a bizarre, specific thing - underwear. It's like I never modelled clothes.

I’m not saying we had a playroom, but I’m not shocked by the sex in the book. It’s essential to tell the story. I can’t believe films that don’t invoke a sexual side of it. So it works for me.

Essentially I feel like all of that pressure when you're making the first of a franchise of [movies based on] books that mean so much to people that has so much attention on it, it can be quite paralyzing I think. I think a lot of that creeped in the first time around and it maybe affects the work.

It's a tiny industry. Actors all know each other to a point where you always know someone who knows the other person who worked with them.