Drawn from true-life events, David Cronenberg’s ‘A Dangerous Method’ chronicles the turbulent relationships between fledgling psychiatrist Carl Jung (Michael Fassbender), his mentor Sigmund Freud (Viggo Mortensen) and Sabina Spielrein (Keira Knightley), the troubled but beautiful young woman who comes between them. Into the mix comes Otto Gross (Vincent Cassell), a debauched patient who is determined to push the boundaries. In this exploration of sensuality, ambition and deceit set the scene for the pivotal moment when Jung, Freud and Sabina come together and split apart, forever changing the face of modern thought. ‘A Dangerous Method’ is set for release November 23rd in the US, and Febuary 10th in the UK.

How was it playing such eminent and revered men, men with such a complex history? Other than the script there’s so much material to look at about Sigmund Freud and Carl Jung.

Viggo Mortensen: The fact that there’s a lot of material that Sigmund Freud wrote, a lot of material written about him, that actually made it a lot easier. I was a little hesitant to say yes at first because it seemed like a big stretch, in terms of my idea of what he looks like, from photographs, my idea of him felt like a bit of a leap. If it had been another director maybe I would have said no, I might have been more cowardly about it (laughs). But with David Cronenberg I knew I would have been in good hands with him and his crew, I’d get to see Vincent Cassell again, and also the fact that Michael Fassbender was gonna play Jung and that Keira Knightley was in it – also as I found out, Sarah Gadon, who plays Emma Jung, she’s a really good actress as well. There were many more reasons to say yes and take the plunge than to say no.

It was an education, it was an education in terms of acting, using different tools, speaking a lot more, speaking really well written words. Christopher Hampton’s script is like a very well laid out well manicured garden with very exotic blooms, in the shadows of which are really disturbing little creatures and secrets (laughs). It was a lot of fun to play as an actor, just the fact that the characters speak so much, I don’t usually get a chance to do that, even in David Cronenberg’s movies. For once he couldn’t tell me to shut up – I had to speak (laughs). We had a lot of fun, David’s sense of humour seems to be not unlike Freud’s, his kind of whit and intelligence. I think you could say about David what the New York Times said about Freud shortly after he died, which was that he was the most affective disturber of complacency in his time, I would say David’s right up there – maybe with Noam Chomsky (laughs).

How about you Michael as Mr Jung?

Michael Fassbender: Like Viggo said it’s always easier if there’s information available to you, and there is a lot, on both characters. And then there’s the fear element, you know, playing someone with a very passionate and vocal following , loyal following. So you want to do justice to the character, you want to do justice to David Cronenberg and Christopher Hampton’s script. Kind of echoing what Viggo said, the main thing for me was to tackle the very eloquent muscular piece of dialogue. I sort of tried to treat it as a piece of music. I spent a lot of time with the text, trying to get the rhythms, find the different rhythms, just to get a power over the dialogue. Because again, we’re dealing with a period in time when discourse, especially in the academic world, it’s a weapon. If your not in charge of it your gonna get destroyed, so that was definitely an element that needed work. And then you just put it all together and see what you come up with. I think what’s interesting when your dealing with real heavyweight characters like this, real revered characters, you find out that there’s human beings underneath, they have egos, they have some very basic and obvious flaws, to play with those elements is also fun.

Is the approach different, playing someone who people may have a set idea about compared to playing a completely fictional character?

Viggo Mortensen: In the end, no matter how much research you do, or how good the script is, or how historically accurate, or how interesting the material is, or how well known the character is – in the end your going to be adding yourself, your human body, your adding your voice, your adding your mind, your adding your feelings to it. People asked me during the ‘Lord of the Rings,’ “Do you feel a greater responsibility playing Aragorn?” I’d always reply, “No, I’m just playing the character,“ I learn as much as I can about the character however, so I don’t make an ass of myself (laughs), and the same goes for Sigmund Freud.

I was aware of the fact, just on the practical level, that I had a lot more dialogue, it was a challenge I really enjoyed. David and I agreed on, just based on the research, that he had a wicked sense of humour, he had a lot of whit and he appreciated it. The 19th century and the beginning of the 20th century in Vienna, and a lot of other places, it was pretty straight laced, in a lot of ways censorship laws were very strict. Freud appreciated wordplay, he appreciated whit, some of his favourite writers were humorists who got around the censorship laws by being clever. Even though the character in this case doesn’t out and out tell jokes, there’s a certain irony to the character, we were following the script but we were also trying to find a little bit of irony and humour. But I don’t feel differently about a character I imagined almost completely compared to someone people have a very set idea about.

Michael, your character in ’Shame’ would be a great patient for Freud. What order did you do the films in, and did the research for one help inform the other?

Michael Fassbender: (Laughs) No, the order was ’A Dangerous Method,’ ’X-Men: First Class,’ and then ’Shame’ – so I was manipulating metal in-between (laughs). It’s funny because when I do a film, I’m sort of in that, it’s a very intense time, the preparation and filming of it. And then I kind of discard it pretty quickly. So when I was doing ‘Shame’ I didn’t even think about the parallels, I didn’t even think I could take some information from what I gathered on ‘A Dangerous Method’ – I might have been doing it subconsciously though (laughs), but I certainly wasn’t aware of it.