Q. In a year that has seen you starring in X-Men: First Class, Jane Eyre, Haywire and Shame, was Shame the most challenging role for you?

A: Yeah, I think so. It was the fifth film out of six films in 20 months, so I was really going into it, I guess, somewhat sort of tired [smiles]. I also went into it pretty intensely. I think it was eight weeks all in all… three weeks pre-production, five weeks filming and I sort of lived pretty closely and intensely with the project and the character for that time. So, obviously you're dealing with somebody who doesn't really sort of hold himself in very high esteem; in fact, he doesn’t like himself very much. So, he's punishing himself quite a bit. And that can sort of take its toll [smiles again].

Q. What did you think when you first read the material? It's obviously very different from Hunger, your first film with Steve McQueen...

A: Yeah, the first time he mentioned it to me was in 2006 and it seemed very obvious to me. I was like, of course, that would be the right story to tell and the right sort of subject matter to investigate. It seems to be a very relevant story and a very contemporary story, so he told me the idea and it was two years later that I actually got a script. I'd already agreed to be a part of it. So, then when I did get the script I was just taken aback by how beautiful the story was told and how eloquent and respectful and a real true insight into this condition. That's what I really thought when I read it.

Q. Did you ever have to think twice about some of the more graphic sexual content?

A: It wasn't a question for me, no. There's always a choice, of course, but I'd made my decision and once I make that decision it's about committing to it really and making sure that I don't drop the ball and I hold up my end of the bargain. So, that's really where the fear element is. Of course, you realise you're going to be doing some pretty sort of intimate stuff in front of the camera but my main fear is that I could manage to bring this living, breathing character that's believable and respectful and true to the story. The rest, then, is about getting on with it and committing to it.

Q. Was one of the main attractions the nature of the material and sexual addiction and the fact that it's not something we see very often discussed on-screen?

A: Yeah absolutely. I mean there are films like Carnal Knowledge, I suppose, that have touched on it… Addiction, The Man With The Golden Arm, these various films. But in recent times, for sure, nobody seemed to be dealing with it. It seemed to be in the media, in and around people's consciousness but nobody seemed to be tackling it. So, that's why it seemed to me to be an obvious thing to approach, look at and investigate because it is real, it is happening and a large, large number of people claim to be suffering from it. And at the same point it's not officially recognised as a disorder or an addiction, so I thought there was definitely enough there to make it worth investigating and a worthwhile subject that could at least pose some questions and provoke some thought and reaction.

Q. How did your own attitude towards sex addiction change over the course of making the film?

A: I suppose at the beginning you think, 'oh well, what is it really?' Is it real? For sure, those were the questions I thought of first but then you start to research and you get to meet people and then it becomes really real very quickly and pretty heavy. You then start to see how many lives really get devastated by it. And then for me there's no question that it is a real disorder and one that should be taken very seriously.

Q. Do you think the easy availability of pornography makes it easier for people to indulge their addiction and harder to overcome?

A: I think it's definitely an element. If you look at some case studies I was looking at, or scenarios... there was a guy who would sort of lock himself into a room for 72 hours and continually masturbate over Internet pornography but can't have sex with his partner. I thought: "Wow, that's a very bizarre sort of thing but a very real thing." I took it very seriously very quickly I suppose once I started looking into it.

Q. How did you manage to get the real-life sex addict you spoke to as part of your research to open up to you?

A: I think it's very difficult when you're talking to somebody like that [because] you're trying to sort of essentially extract information out of them. So, by asking them direct questions it's not really so effective... people tend to be on guard a little bit more. So, I just asked him to tell me stories and from those stories I could get an idea of where certain motivations were born within a personality like that and how somebody suffering from this condition actually deals with it in the situation. It's sort of how it manifests itself physically, where even the idea of an embrace is something you want to squirm your way out of. So, that helped me sort of get a physical life for that sort of inner life, if you like. It really helped meeting somebody. And then I just worked a lot with the script.

Q. Where does the line between addiction and a man's fascination with sex begin and end? At what point do you cross the line into addiction?

A: For me, addiction comes down to basically where a pattern of behaviour has developed and that pattern of behaviour is becoming a very damaging cycle. It's sort of damaging your relationships, friends or lovers, it's damaging your own personal health and it's damaging for you and your workplace. So, those things combined and the knowledge of that and yet it's still very, very difficult for the individual, if not close to impossible, to break that pattern. That, for me, is addiction. If a guy is sitting in his office and can't get through the day... it's all encompassing. Yes, men think about sex a lot. I know that. I'm a man. There's things that you can relate to from Brandon.

But it's the extremes... it's the fact that it's all encompassing; all his compulsions are revolving around his relationship with sex. He's not a stupid guy but when he's on his computer he knows that surging Internet porn on his work computer is a dangerous thing to do but the fact that he can't get through a day in the office without relieving himself, masturbating, that becomes... so it's not only masturbating once a day, but 20 times a day. It's when the balance tips, like anything else in life, in a direction that's damaging. You have someone in Brandon who is engaging in these very physical and intimate acts but without any real gratification, or any real enjoyment, and no intimacy.

Q. How has your relationship with Steve evolved since making Hunger together? And how does that compare with other directors you've recently worked with such as Ridley Scott or Steven Soderbergh?

A: Yeah, you sort of work with masters of their craft and all of the people that I have been working with that can be said for them. I suppose with Steve we met at a crossroads in both of our lives with Hunger. It was an opportunity that was amazing for me to play a lead role in such a demanding piece and be allowed to show some possibility within the profession of what I could bring to it... my capability. And so that changed my life and together we were very passionate about what we were doing. It was his first feature film, so there was an air of fear for him too.

But I think we have chemistry and we just sort of bonded very quickly and it became a very strong bond very quickly. After Hunger, once the foundations were laid, I was worried and I had fear that hopefully we’d find that work rate again in Shame and that understanding of one another, that sort of passion of searching for the same goal. And it happened like that... it was almost like walking off Hunger and walking onto the set of Shame.