Actor Jesse Eisenberg poses for a photograph in Toronto on Wednesday, May 29, 2013. A shift in his shoulders, a change in his gait and a fresh facial expression were often all Jesse Eisenberg needed to convincingly transition between two characters who were physically identical but emotionally entirely different in "The Double." THE CANADIAN PRESS/Nathan Denette

TORONTO - A shift in his shoulders, a change in his gait and a fresh facial expression were often all Jesse Eisenberg needed to convincingly transition between two characters who were physically identical but emotionally entirely different in "The Double."

But the experience didn't just end when the cameras stopped rolling — the actor best known for playing Facebook co-founder Mark Zuckerberg in "The Social Network" found himself behaving more like one character or another depending on which one he played on a given day.

"It just ends up infiltrating the feeling you have about yourself. With the more confident character I felt better about those scenes just because while you're acting in them you're feeling good about yourself," he said.

"Only in retrospect do you realize that you were kind of taking on the feelings of the role."

The film, which is based on a novella by Fyodor Dostoyevsky, tells the story of an incredibly mild-mannered, almost socially invisible man who suddenly finds his life turned upside down when his doppelganger shows up.

Eisenberg, who plays both the meek Simon and his extroverted polar opposite James, found that alternating between both characters amounted to a filmmaking experience he could relish.

"In terms of switching back and forth it was just a lot of fun. It kind of kept it fresh," he said. "The way movies are shot is so laboured that by the end of the day doing the same scene over and over can feel really boring, but I never really had that experience."

Eisenberg did, however, have to deal with watching his own scenes repeatedly so he could act alongside himself — an uncomfortable scenario at first, but one that he later turned to his advantage.

"That's like generally something I don't like to do ... but this was kind of necessary," he said of having to scrutinize himself on screen.

"Ultimately it was a really fun thing to do because you can kind of take your own pace. I can kind of do something with one character to highlight what I want to highlight in the other character."

The entire film plays out in an unsettling, dystopian world that isn't rooted in any specific time or place. There's barely any sunlight and not a single shot of the sky.

British director Richard Ayoade deliberately made those decisions as he set out to create a piece that was slightly surreal.

"It was all meant to be in a kind of dreamy feel," he said, adding that he wanted the film to be left open to interpretation.

"What I find very frustrating is when people say who am I meant to relate to in this film, as though essentially it's meant to be like an arcade game where you're the centre and the character is merely a kind of experiment to see how you would have reacted."

Strange as the film is at times, it is also punctuated with moments of dark comic relief.

Basing the movie around a doppelganger, in particular, was something Ayoade thought had great potential for humour.

"Someone has this person who looks exactly like him and no one notices, but even when people do notice this doesn't bother them. And there seemed to be something very comic to me about it," he said. "No one had ever done anything, I think, like that."

Mia Wasikowska, who plays Simon's oblivious love interest in danger of being lured away by the charming James, was attracted to Ayoade's creative approach.

Having two characters who look exactly the same — right down to their drab suits and shaggy haircuts — with diametrically opposed personalities lent much depth to the film, she said.

"Whether the internal you will ever kind of match the external version of you and whether those two parts of you ever align is kind of an interesting thing to explore," Wasikowska said.

"There are so many ways you can interpret (the film) and I think each individual will have a different perspective on it."

"The Double" opens in Toronto on Friday and will be released in cities across Canada later this month.

News from © The Canadian Press, 2014