TORONTO - For some actors, film festivals are like a citywide game of musical chairs.

They move from this hotel to that one, from this red carpet to that photo shoot, from this press conference to that cozy Q&A, but actor Viggo Mortensen stops the music and asks the five reporters sitting at a table where each lives.

Clad in a blue shirt and gray suit, his hair just past his collar, Mortensen was in Toronto for A Dangerous Method. He was soft-spoken and polite as he sipped hot tea and talked about playing Sigmund Freud to Michael Fassbender's Carl Jung and Keira Knightley's Sabina Spielrein.

Freud and Jung had what director David Cronenberg cheekily calls a "bromance."

The first time the men met, in 1907, they talked for 13 hours straight. The last time they were in the same room, in 1913, they exchanged not a single word, according to the John Kerr book that partially inspired the film.

Mortensen wasn't available the first time Cronenberg asked him to play Freud, but when Christoph Waltz dropped out, the director returned to the actor who had starred in his A History of Violence and Eastern Promises.

On a technical - and talky - level, it was a challenge.

"Usually, the characters I play, including for David, are men of few words who communicate largely in nonverbal ways. We all communicate in nonverbal ways, including Freud, but he really uses words to manipulate, seduce, attack, defend, parry, evade.

"That was really fun, once I got the hang of it and got comfortable with the great dialogue that (screenwriter) Christopher Hampton wrote," he said.

"A lot of times that happens. The thing that seems like the biggest challenge and 'This is not going to work, I don't know how to do it,' once you crack it and get comfortable, it ends up being more enjoyable than things that come easier."

The story is set on the eve of World War I in Zurich and Vienna where Jung and Freud, respectively, live.

"I thought he was an old, white-haired, frail, rigid, formal person," the actor acknowledged. "But those images are from when he was quite a bit older, sickly with cancer, his last 10, 15 years."

Naysayers who didn't like or understand Freud's ideas may have called him an inflexible fuddy-duddy, but Mortensen came to like the man he considers "warm and engaging and fluid."

Although Mortensen did his usual meticulous research, he made an important realization on the first or second day of shooting.

"A very significant part of what I was chasing after was right in front of me, and that was David (Cronenberg)," he said. "Because his sense of humor and wit and his intelligent conversation are not very different from Freud's at all, from the Freud I learned about in research."

Freud was shaped, in part, by the anti-Semitism coursing through Austria at the time.

"He grew up in that atmosphere and also in a very repressive atmosphere generally, not just about sex, but free thinking. There were very strict censorship laws in the 19th century in Vienna and one of the roots of his wit - that sort of ironic tone that he has in conversation - is a self-defence mechanism, a way of getting around censorship and anti-Semitism."

He dodged censors with wordplay, talking about something without ever naming it, like favorite Austrian comic dramatist Johann Nestroy.

"Freud was the son of a Jewish merchant who had to move his whole family to Vienna because he couldn't get work. He, as a boy, had to watch his father be mocked and abused on the street for being Jewish. ... You develop a thick skin and you develop a certain kind of wit to defend yourself, if you have no other means.

"Famously assigned to sum up his colleagues' hours-long deliveries at a conference, Freud quipped, 'Well, a great many words have been spoken today and they were so clever that I didn't understand a single one.'

"Or he might preface a statement or idea out of left field with, 'As all of you know.' It was a gesture of generosity and good manners, but also a calculating one designed to recruit people to his side."

Donning brown contacts, wearing a subtle gelatin nose, sporting a beard and moustache and clenching a cigar Freud allowed the actor to flex different muscles than as a homeless father, Russian mobster, diner operator who fatefully foils a robbery or Aragorn in Lord of the Rings.

"There's a different discipline that's just as demanding when you're playing a character like I did in Nikolai in Eastern Promises where it's very minimalist but it's very detailed. The same in History of Violence.

"It's very precise and it takes a lot of work to get it right and then, as always, you have to relax and just trust that it's there. You need a director who pays attention to those details.

"It's just as challenging to play someone who speaks a lot because you could talk a lot but if you don't know what you're talking about and you don't find the music in it and you don't connect to the other actor, it can be incredibly dull to listen to and watch."

When he saw the movie for the first time, he was happy to find that didn't apply. "I come to like all the characters I play, but I really like him, I think he's funny and engaging."

Even if the bromance ended in a bad breakup.