Director Tate Taylor had his work cut out trying to convince Chadwick Boseman to portray the late James Brown in a new biopic, because the actor was adamant he would never step into the Godfather of Soul's shoes.

Boseman admits he really wasn't interested in tackling the lead role in Get On Up after experiencing the intense pressure of playing a real-life icon in 42, in which he brought baseball star Jackie Robinson back to life onscreen.

He tells Entertainment Weekly, "Somebody said something to me about the script and I was like, 'No, I'm not going to even read it.'

"It felt like one of those roles that nobody should try, ever. And I had just gone through so much scrutiny doing a biopic. Nope, I'm not doing that."

Despite Boseman's concerns, Taylor managed to get him to perform Brown's funk song Say It Loud - I'm Black and I'm Proud for a screen test - and it was only then that the actor was won over by his own talents.

He explains, "I needed to see the wig. I needed to see myself on stage."

Boseman perfected the soul legend's difficult dance movies and singing skills for the movie and his efforts even left Get On Up's producer, Rolling Stones frontman Mick Jagger, impressed.

He recently stated, "James Brown was a fluid, supper aggressive mover, so for Chad to learn and do that is quite an achievement."