Get On Up, the film of James Brown, is essentially like most biopics; a rags-to-riches summary of its subject's milestones, successes and failures. Under the direction of Tate Taylor (The Help), the movie does not flinch in shining a light on the Godfather of Soul's tyrannical behaviour and mistreatment of those closest to him; notably, his second wife Dee-Dee (Jill Scott), as well as long-suffering band-mates led by Bobby Byrd (Nelsan Ellis).
But responsibility for the film's success rests solely on the largely unknown shoulders of Chadwick Boseman, 42, who impressively morphs into the famed musical legend. His frenzied dance moves are spot on and, unlike most music biographies in which the actor mimes over original recordings, Boseman's voice (and signature Brown scream) are also heard in the film.
The film has garnered mixed reviews, though Boseman's blistering performance alone has drawn wide praise. It is a gamble that clearly paid off for the initially hesitant actor. "I was extremely nervous about taking on the role, says Boseman. "When I first heard of the script, I wouldn't even read for it. I thought it was impossible to do, and actually, I thought nobody should touch it. But once I started, I got over the fear. It was a process. I threw myself into learning how to dance, which I studied for five days a week for five hours. It was also understanding his vocabulary and it was a step-by-step journey of thinking, 'Today I will conquer one thing'. It could have been one move or one scream."
Watching Boseman's performance as Brown, it's not always possible to distinguish between his own vocals or the original Brown recordings. "Most of the live music is him. There is one version in the film of Please where it's all me and there are some other moments that are not the recordings where I'm singing."
The film reveals many sides to Brown, including his grim beginnings (for which he is played by twins Jamarion and Jordan Scott) in an impoverished and violent household in rural South Carolina. A cruel father (Lennie James) and neglectful mother (Viola Davis) help to explain the origins of his dark side.
"I understood the darker side of him because of what he had to go through. He got a lot of flak for being so hard on people but he worked hard to get there," says Boseman. "It's not even that he was from a one-parent household, he had a no-parent household."
Brown spent his formative years raised by his aunt (Octavia Spencer) in her brothel. "James Brown came out of that situation and then juvenile detention [where he spent three years at the age of 16 for theft] and yet he had a positive outlook," he says.
Playing such an over-the-top character can be a difficult tightrope to balance on, while trying to avoid caricature and maintain realistic acting performance.
Says Boseman, "It was the most difficult challenge but I looked at it like a classic Greek tragedy, it was putting on the mask."
Or in his case, it was putting on 30 different wigs. He laughs. "Oh, the wigs were fun to wear. His hair was always changing, almost daily. It was crazy."
But if he could take off the hair, Boseman still took a while to shake off being James Brown.
"I needed to do a James Brown exorcism when the shooting was over and I didn't listen to his songs for over a month.
"Once you walked in those shoes, it's hard not to carry at least a piece of that with you, a bit of that swagger with you. So I didn't leave it all behind.
"There are certain things you don't want to get rid of."
What: Get On Up, the James Brown biopic produced by Mick Jagger
When: Opens October 16