'Sex addiction is a grey area'

The Irish-born star takes on the part of Brandon, a man dealing with his intimacy issues in new movie Shame, and while many people may know about the problem, he thinks few believe it to be real because they have only heard about it because of celebrities such as Michael Douglas and David Duchovny, who have both been treated for it.

He told BANG Showbiz: "I suppose, you know, like everyone else it seems to be kind of a grey area, this idea of sexual addiction. All of us were introduced to it through celebrity stories and I suppose the public perception is it's sort of self-indulgence perhaps in that world."

Mental illness

However, he believes researching the film helped him learn there is far more too it than that because he spoke to normal people who suffered.

He said: "What was interesting to discover is just how many people are claiming to suffer from it and it wasn't being treated as an official mental illness, it's just the various sort of factors.

"What was very important to Brandon was this problem of dealing with intimacy and emotional content in any sort of relationship. And so, trying to find that was I suppose the hard part because everything stemmed from that. So I was very grateful, I am very grateful, to meet somebody who was going through exactly that."