Michael Fassbender felt so overwhelmed while shooting Shame that he feared he was going "cuckoo".

The actor plays a sex addict on the edge in the Steve McQueen-directed movie. Michael threw himself into the role, which required full frontal nudity and explicit sex scenes. He admits that playing such a complex character took its toll once the cameras had stopped rolling.

"One particularly bad day when I got back to my trailer, I was a bit confused, and very raw," he told the March edition of UK magazine Marie Claire. "I did think to myself, Oh, man. You're going a bit cuckoo!'"

The 34-year-old star's latest big screen outing sees him in another controversial movie, A Dangerous Method.

In the film, Michael plays Swiss psychiatrist Carl Jung whose relationship with Sigmund Freud becomes strained when he embarks on a romance with a patient.

Keira Knightley plays Russian love interest Sabina in the film and some scenes involved Keira and Michael's characters indulging in S&M.

"It's always embarrassing and awkward when you do stuff like that. You try to keep the atmosphere light. I always hope the other person feels relaxed and trusts I'm not going to take the p**s," Michael explained. "It's like, Did that hurt? This is going to leave a mark!' I didn't want to actually hit her. So I was concentrating on hitting the mark, and not actually hitting Keira."

Michael who was born in Germany and spent his childhood in Ireland had his own personal experience of therapy. He attended counselling sessions with a former girlfriend.

"It was something I thought I would try out," he added. "And I do think it's a very helpful process, if there is an improvement at the end of it."