Ridley Scott has said it would be impossible to finance films if his lead actor was an unknown called "Mohammad so-and-so from such-and-such".
Responding to months of criticism over the apparent lack of ethnic diversity in Exodus: Gods and Kings, the Gladiator director brushed off the outrage by insisting that, had white actors not filled most of the key roles in his upcoming biblical epic, it would never have got off the ground financially.
"I can't mount a film of this budget, where I have to rely on tax rebates in Spain, and say that my lead actor is Mohammad so-and-so from such-and-such," he told Variety.
"I'm just not going to get it financed. So the question doesn't even come up."
Oscar winner Christian Bale (The Dark Knight, The Fighter) plays historically Middle Eastern character Moses in Exodus, while white actors Joel Edgerton and Sigourney Weaver star as Egyptian Pharaoh Rhamses and Queen Tuya respectively.
Ethnic minority actors do feature, but in secondary roles (Ben Kingsley as Nun, Golshifteh Farahani as Nefertari and Indira Varma as Miriam, for example).
Scott addressed his critics last August by assuring film fans that Exodus would represent "a confluence of cultures".
"There are many different theories about the ethnicity of the Egyptian people and we had a lot of discussions about how to best represent the culture," he told Yahoo.
"We cast major actors from different ethnicities to reflect the diversity of culture, from Iranians to Spaniards to Arabs."
Edgerton also responded to complaints, acknowledging the "whitewashing" accusations as fair. "It's not my job to make those decisions, he told SBS. "I got asked to do a job and it would have been very hard to say no to that job. But I do say that I am sensitive to it and I do, I do understand and empathise with that position."
However, a protest was soon launched on Twitter urging cinema-goers to #BoycottExodusMovie.
Scott's film is not the only one to come under fire for its allegedly racist casting. Upcoming Warner Bros movie Pan has been criticised for casting white actress Rooney Mara in the role of Native American princess Tiger Lily.
The Hollywood Diversity Report, published earlier this year showed that only 11 per cent of films cast an ethnic minority actor in a lead role while ethnic minority actors made up just 10 per cent of the cast in the majority of movies.