Don Cheadle says Ewan McGregor is the reason the upcoming Miles Davis biopic got made.

The 51-year-old actor stars in and directs Miles Ahead, a film focusing on the life of the late American jazz musician. Ewan portrays Rolling Stone journalist David Brill, a role that Don believes helped secure the project.

"Only if I got a white actor to be in it some way," he told when asked if the film could've been made sooner if things went in a more traditional route. "And that's the reality. That's when the money got triggered, is when we cast Ewan McGregor. They would have said, 'That's great, I love the whole idea and the Miles music, now where's the white guy?' (laughs) That's what the question continued to be.

"But pre-dating any Ewan involvement, when (Miles' nephew) Vince Wilburn Jr. announced at the Rock and Roll Hall of Fame inducting ceremony for Miles Davis in 2006 that they were going to do a Miles Davis movie and I was going to play him, which had not been told to me, people started calling me and asked when the movie starts and I'm like, 'What are you talking about?'"

Luckily Don jumped on board the movie and felt he had to helm it too, though admits he had second thoughts when it all suddenly became real. One important lesson he learnt from working under the direction of filmmakers is that he needed to be "ego-less", and had to be open with ideas.

During his interview the actor was also quizzed on his opinion on this year's (16) Oscar nominations. The lack of diversity has caused an uproar amid celebrities and film fans alike, and Don previously commented that it's the result of a bigger picture. It won't stop him from attending the ceremony in February though.

"Boycott the Oscars this year? With Chris Rock as the host? In this moment?" he mused. "No chance in hell. I think this could be a career-defining moment for him. And there's no better person to do it. He should skewer everybody."