A number of celebrities have spoken out against bosses behind the annual Hollywood awards gala, threatening to pull their support after no black stars received nods in the main acting categories for the second consecutive year.

Will Smith and his wife Jada Pinkett Smith have both vowed to boycott the ceremony, and director Spike Lee has also decided not to go, and Reese Witherspoon, Dustin Hoffman, and Mark Ruffalo have all since spoken out on the subject.

Viola, who received Oscar nods for her roles in Doubt and The Help, has now waded into the row, and insisted movie executives need to provide more quality movies for black castmembers.

"The problem is not with the Oscars, the problem is with the Hollywood movie-making system," she tells Etonline.com. "How many black films are being produced every year? How are they being distributed?... You could probably line up all the A-List black actresses out there (and) they probably don't make what one A-List white woman makes in one film. That's the problem. You can change the Academy, but if there are no black films being produced, what is there to vote for?... You cannot win an (award) for roles that are simply not there."

When asked whether Chris Rock should step down from his role as Oscars host, she adds, "Like I said, the Oscars are not really the issue. It's a symptom of a much greater disease. But if he does, I hope he takes it as an opportunity to make a statement, a social statement about change. It's 2016."