Adrien Brody has played a Holocaust survivor, and a fox. But even someone with his experience found mastering the Australian accent "pretty challenging".
"It's very specific," he said. "There are many different dialects within it. Playing a man from Melbourne is very different than playing someone from regional New South Wales.
"Accent work is very challenging anyway, because you have to make it sound like it's your own, not just get the phonetics. You have to find the right tone for it as well."
The accent in question belongs to BackTrack's Peter Bowers, a psychiatrist who, while coming to terms with the death of his daughter, slowly realises that all his characters are ghosts.
"It delves into this deep, conflicted space that he's living in," said Brody. "Grief, a sense of guilt that comes with a parent's inability to prevent certain things. It wasn't a pleasant place to live in."
Playing a string of deeply troubled characters takes its toll, and Brody admitted that he finds the experience gruelling, although ultimately transformative.
"You do keep a bit of it, always. You keep a sense of understanding, for sure, if you look at the characters that you embody and make a part of you for extended periods of time.
"You share that experience, and learn from it, and gain some empathy. You won't be the same afterwards."
Brody says, however, that the emotional rollercoaster is an essential part of the process.
"It should be. It needs to be. Why should I expect an audience to believe something if I don't believe it."
He says that music is a useful way to bring him back into himself while shaking off particularly painful roles. His genre of choice is somewhat unexpected: hip-hop. He once shocked by reading out the lyrics to The Notorious B.I.G.'s Ten Crack Commandments at the Lincoln Centre's Academy of American Poets.
I felt that Christopher Wallace, Biggie Smalls, should be given his credit," he said. "He was a prolific American poet, and there is no denying that."
It turned out to be controversial choice.
"There were jaws on the floor,' he laughs. "There were audience gasps."
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