Oscar-winning screenwriter John Ridley has heaped praise on Outkast star Andre 3000 for the lengths he went to to perfect his portrayal of rock legend Jimi Hendrix in new biopic Jimi: All Is By My Side.

The Brit, who adapted Solomon Northup's 12 Years a Slave memoir for the big screen, admits he was blessed when the Ms. Jackson singer was cast as Hendrix - because the hitmaker, real name Andre Benjamin, really wanted to become the guitar great.

Ridley tells RollingStone.com, "I got a musician who can act and an actor who could play. Andre is just a unique talent, and part of that talent that you see also came from a lot of hard work. The first time I met him, he had a curiosity about the world that was equal to what I believe Jimi's curiosity about music and the world was at that time in his life.

"He's got the physicality, he's got the emotional curiosity, he's got the charisma - so, to a degree, he's already there.

"Andre came out to L.A. in January of 2012 and worked with me through April on all aspects of Jimi, from watching video of him to working with a vocal coach to getting as slim and slender as Jimi was at that time period. He didn't just work on playing the guitar, but playing the guitar left-handed.

"That's four months of Oscar-level work as an actor, then another month of working with the actors in Dublin (where the film was shot), and then another month-and-a-half of shooting. That's about seven-and-a-half months of work. He gave that performance because he wanted it.

"It was never going to be a Vegas lounge act. It was always going to be about getting to an emotional honesty with this character, and I cannot say enough about what Andre did."