The Hotel Rwanda star admits the project, in which he portrays the jazz great and directs, would never have made it as a movie if the Scottish actor hadn't signed on to play opportunist journalist Dave Brill.

And Cheadle reveals that was partly because studio bosses feared not enough people knew who Miles Davis was.

"When we were putting this together I would do a survey: 'Miles Davis, what comes to mind?' People would say, 'He's a musician, and he's black...' but some people weren't sure what type of music he played, so we'd lose people there.

"It's still not a big percentage of the general population who know Miles Davis; who he was, what he did, what his music is. A lot of people think jazz is something playing in a cocktail party or on an elevator. They don't really think about it as American history, and so it wasn't surprising to me that it was difficult to get this movie done.

"There were some attempts that predate me about 20 years. They've been trying to get this movie done for a long time. Ewan (MCGregor) was high on the list to play Dave Brill and we wrote that character in the script in 2008. Ewan was someone we had hoped to get and we were fortunate.

"Once Ewan said yes it got the ball rolling financially for us. The realities of making movies at this budget level... you have to have a foreign market sales strategy and something that plays overseas and not just the domestic market. And Ewan checked all of those boxes for us and he's a great actor, so it's a win, win."

And Don admits Miles Ahead, which was a passion project of his for so long, has opened new doors for himself as a writer/director: "I've been offered several things to direct since this, which is great," he tells WENN, "but I'll probably take it on after a long nap!"