I'm very interested in religion as something to study, but I'm not a religious person in the slightest.

What first attracted me to doing Swiss Army Man was just how mental it was - how insane and wonderful and original the script was.

I see myself doing Harry Potter films as long as I'm enjoying it and as long as they are going to challenge me as an actor. I want to be an actor - it's my aspiration - so I want to do other films. I want to write something and I want to direct something!

I basically have the diet of a 19th-century Irish navy, apart from the litre of stout a day. It's meat and potatoes and bread and cheese: those are my four food groups.

It was a lot of fun to play a character [in Swiss Army Man] with no inhibitions, and with no knowledge of the world, and who comes into the world kind of like a blank slate. It means there's no template or blueprint for how you need to play certain scenes.

You have to find out who you are aside from what the media say you are. If you've become reliant on them for kind of a sense of self, then you're really screwed.

I'm never going to be in something as commercially successful as 'Harry Potter' ever again. It's impossible. So that gives me incredible freedom to go off and make the slightly off-the-wall films that I want to make.