David Cronenberg thinks people are too focussed on the spanking scenes in 'A Dangerous Method'.

Keira Knightley plays the role of Sabina Spielrein - who finds sexual gratification in spanking - in the movie about the relationship between Carl Jung and Sigmund Freud but director David Cronenberg says this is only a small part of the film.

He said: "There is not a lot of spanking . Only two shots . But in people's minds . In 'A Dangerous Method' there are two shots, literally of spanking. But the impact of the spanking, not to make a joke of it - is an innate part of what the movie's about. Speaking things that were unspeakable at the time."

Viggo Mortensen - who stars as Freud - in the film revealed he only took on his role because David was directing the movie.

He told Shortlist magazine: "If someone else had asked me to play this role, I would have hesitated. But sometimes it's good to be put in a position that you're not used to, where you're forced to try something."