'The Martian' actor Chiwetel Ejiofor says we won't know if Hollywood has fixed its diversity issue for a generation

British actor Chiwetel Ejiofor, 38, had been a steadily working character actor for most of his career until he scored the lead in 2013's "12 Years a Slave," and shifted higher up the Hollywood food chain as his powerful performance led to a Best Actor Oscar nomination.

Since then, he's had a major role in the fall hit "The Martian," and he co-stars opposite Julia Roberts in the upcoming thriller "Secret in Their Eyes" (in theaters November 20). He's also currently shooting the upcoming Marvel adaptation "Doctor Strange," in which he plays the evil Baron Mordo.

The roles for Ejiofor have come fast since "12 Years a Slave," but Hollywood is only slowly addressing a lack of wide representation in its movies.

Ejiofor's character in "The Martian," NASA's Mars mission director, was of Asian descent in the book it's based on, which led to the movie being criticized by the Media Action Network for Asian Americans. (On the other hand, Baron Mordo in the comics is a white man.)

So is Hollywood finally addressing its diversity issue?

"It's too early to tell," Ejiofor told Business Insider on Tuesday from the set of "Doctor Strange." "I feel these things will probably be judged generationally. When we look back at this time in cinema, we'll be able to understand a bit more whether diversity was addressed in any way, or if things improved from the '90s and the 2000s. It's hard to say."

Ejiofor said one thing that makes him believe there has been progress is the casting for "The Martian."

"I feel the film is a great example and a very successful example, I think, of diversity in cinema. Though I suppose one isn't going to please absolutely everyone," said Ejiofor, referring to the complaint by MANAA.

African-American, Mexican, Asian, and female characters make up many of the lead roles in "The Martian," which has been one of the most successful films of the fall, having grossed over $450 million worldwide.

"I think it was great to have so much diversity in that film, and that film being so successful, it is a prototype for how films can do that more. It was something I was personally very gratified with."