Liu insists the best acting comes about when stars are able to morph into an unfamiliar role.
She says, "I think that's reverse racism.
"I think Rob has an incredible vision and it doesn't matter. If you don't like the acting that's fine, but I don't think it's fair to go down to the core like that.
"Because we can just tear apart everything else that has happened - Meryl Streep can't have an Italian accent or be from any other place because she's American. Or Chinese actresses can only play Chinese, and I'm Chinese-American so I can only play Chinese-American?
"That limits me in every possible way."