Casey Affleck interview

Casey Affleck steps up a gear opposite Brad Pitt in The Assassination of Jesse James

Finally emerging from the shadow of his older brother Ben, Casey Affleck, 32, delivers an Oscar-worthy performance as the eponymous killer to Brad Pitt's legendary cowboy in The Assassination of Jesse James By The Coward Robert Ford.

You've worked with Brad Pitt a lot, having appeared in Ocean's 11 and its sequels, as well as this film. Has he changed much?

I don't think I ever met Brad on the Ocean's movies! So this was a nice opportunity to spend some time with him and get to know him better. I don't think he's changed. Well, he's a little more grey!

Did you grow up watching westerns?

The four movies I can remember seeing as a kid where The Elephant Man, The Magnificent Seven, The Good, The Bad and The Ugly and Mad Max! Two of those are westerns. So the western genre is emblazoned on my memory from childhood, and those are two great movies.

The film alludes to modern-day celebrity culture. What's your experience of the reality of that?

The way people appear in the gossip papers, as they're depicted as celebrities, it's not often much like who they are. The more people I meet, the more that's true. Sometimes, they're worse. Sometimes, I think, 'Well, he's an asshole but he comes off pretty nice in the papers!'

Talking of stars, you've just been directed by your brother Ben, in Gone Baby Gone. How was it taking direction from him?

Well, my opinions are better than his! It was a little excruciating. We just fought, you know what I mean? He'd give me direction. I'd say, 'That's stupid.' He'd say, 'You're stupid.' I'd say, 'This movie's stupid.'

Did it help that the film was made in Boston, where you grew up?

It was shot in our old neighbourhoods, so it was a lot like going home. Which was great. It definitely helped me to make the movie. I was so familiar with where I was, what street I was on, what kind of people lived here, the accent…it was easy for me.

The Assassination of Jesse James By The Coward Robert Ford opens on 30 November.