The 'Selma' star has revealed that money doesn't mean anything to him when it comes to choosing which films he will appear in.
He said: ''I'm in this for the long haul. I truly believe in cinema's potential for cultural impact. I have a clear idea what I want to do - to enrich people's lives.
''Now I know not everything is the same as playing Dr King. 'Rise of the Planet of the Apes' is not a film I walk away from thinking, 'OK, that's fundamentally about the enrichment of people's lives.' But it is thought-provoking.
''And the fact that it smuggles elements of the civil rights movement into the story of an ape uprising - well, that has value. For me, it's a very conscious decision to follow my heart rather than the dollar.''
The 38-year-old actor also revealed that he ''hunts'' down parts which could be played by any actor, in a bid to stop the racial prejudices of the film industry but admits that with the way the business is now, he is likely to lose out if he was up against a Caucasian actor.
He told The Guardian newspaper: ''When I looked to heroes I wanted to emulate, I constantly found myself mentally jumping over the pond. I had read that Denzel Washington had told his agent early on: 'Give me everything that Harrison Ford is turning down.' That stuck with me.
''I hunt those kinds of roles down. The only way I get a leading role in a studio picture is if Ryan Gosling can't play it, which is clearly the case with 'Selma'. If this was a non-colour-specific character, it wouldn't be