Mortensen explained, "When he was first trying to set the film up he did come to me, but I was unavailable at the time. But I was a bit surprised - I didn't picture myself playing Sigmund Freud at any age. So, it gave me something to think about. Then it came around again the following year when Christoph Waltz, who was then going to do the part, decided he wanted to do another movie instead - Water for Elephants, I guess it was… I said, I could do it but I hesitated a little.
He added, “But being that it was David, I trusted him, and I've had great experiences working with him before and I know the importance he puts on casting. So, I thought, well, he must have very good reasons for it." A Dangerous Method also stars Michael Fassbender and Keira Knightley and is set to be released in the UK on February 10.