Golden Globe Best Actor awardee for “The Martian” Matt Damon is a Hollywood A-lister, but his being cast as the lead role in the upcoming Chinese epic movie “The Great Wall” is being questioned.

The question, though, is not over his acting skills but a white actor being cast in an Asian role. Chinese actress Constance Wu, the lead star of “Fresh Off the Boat,” tweeted a long letter on Friday, saying that Damon playing a Chinese warrior who defends an iconic landmark against ancient Chinese monster perpetuates a racist myth in the movie industry that has been existing for long.

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The myth is that only a white man can save the world which Wu busted, citing several non-white heroes such as Mahatma Gandhi, Nelson Mandela and Malala Yousafzai. She pointed out that explanations why films have to be “whitewashed” such as the lack of bankable diverse stars and the need to please foreign investors are invalid, reported CNN.

However, Wu stressed that she does not blame Damon, the studio and Chinese financiers. “It’s not about blame, it’s about AWARENESS,” she wrote in a subsequent tweet.

The movie’s trailer was released on Thursday. The epic film, directed by Zhang Yimou, opens in February 2017. The movie tells of the construction over 1,700 years of the iconic Great Wall of China, using 5,500 miles of bricks and stones to keep invaders out, reported the Daily Beast.

Damon plays a mercenary soldier who was stuck in China on the wrong side of the wall, but becomes a hero by helping other elite warrior beat giant monsters.

However, the website noted that Damon is not the first white actor to portray non-white roles. It cited Tom Cruise who was the last samurai in Japan as another example. CNN also pointed to “Gods of Egypt” which had a predominantly white cast such as Danish actor Nikolaj Coster-Waldau, Australian actor Brenton Thwaites and Scotsman Gerard Butler in key roles.