Look at the Coen brothers. All their minor characters are as interesting as their protagonists. If the smaller characters are well-written, the whole world of the film becomes enriched. It's not the size of the thing, but the detail.

I started hitching about the country when I was 16 or 17 years old. I found the music that was played around the country - Irish music - had a particular resonance.

My grandfather played a mandolin, so I got my hands on that. Then on down to a banjo, and I found I couldn't play any kind of soft or mournful music with that so I took up the fiddle in my late 20s or early 30s - and that was far too late. But it keeps me off the streets. It has been a love of mine since I was 17 maybe.

As an actor, to get a gift of a part like that is unusual. And then, to have the prospect of another one is always going to be interesting and exciting.

Are there people to aspire to? Can people be strong enough to withstand all of this disillusionment? Maybe the time is right for people to emerge from the easy cynicism and try to get back to a place where we can actually believe in people and trust people to have proper motivations.

You work for it. You don't have to massage it, so that it fits into the way it has to be. He's just too vigorous a writer and the dialogue is too sparking to do anything other than inhabit it and give it as much truth as you can. You just try to make it part of your DNA. That's what the challenge is, really.

I think every character actor at some stage likes to carry a film. It can be extremely liberating to just come in for a scene or two and do your thing. But I find it frustrating if I'm just doing little bits here and there for too long.