"Now, what about that movie about the Great Wall of China starring everyone's favorite Chinese actor, Matt Damon?"

It was just one of a slew of comments on social media in the past few weeks lampooning a huge action movie that is scheduled to hit theaters later this year or early next. The Great Wall, a co-production between China and Hollywood, is the most expensive film ever shot entirely in China, costing more than $150 million.

The movie features Matt Damon, Willem Dafoe and a slate of popular Chinese actors using the Great Wall to defend humanity from a monster attack.

But since the film's trailer was released, journalists and commentators on social media have criticized it for "whitewashing" - replacing roles that could or should be cast with actors of color with white actors.

What is Matt Damon doing saving ancient China, anyway? Couldn't the Chinese handle that one themselves?

The critics definitely have a point - the film industry has a long and troubling history of minimizing actors of color. Some in the industry boycotted the 2016 Oscars, after only white actors and actresses were chosen for the top four categories for the second year in a row.

And movies including Dr. Strange, Ghost in the Shell and Aloha have all recently been criticized for casting white actresses in originally Asian roles, just the latest episode in a long history of whitewashing in Hollywood.

Yet there's also an irony that many have missed. Despite Damon's prominent appearance, the nuts and bolts of The Great Wall are more Chinese than perhaps any major co-production between the United States and China has been before.

Within China, the movie is being hailed as the first of its kind to be made by a major Chinese director, backed by a Chinese-owned Hollywood studio and featuring Chinese historical themes. And if successful, it could mark a step forward for the influence of the Chinese film industry around the world.

The Great Wall is definitely among the biggest budget co-productions, and it's the first very large budget one in which there is a major Chinese creative force behind it," says Aynne Kokas, an assistant professor of media studies at the University of Virginia and the author of the forthcoming book, Hollywood Made in China. "That's the part of the story that's getting left out."

In recent years, Hollywood has begun avidly courting movie-goers in China, the world's second-largest market that could surpass the United States to become the largest next year.

The Chinese film industry is also eager to develop films that appeal to its own audiences but can also succeed outside its borders. Creating a film that captures audiences in both China and the United States has been a Holy Grail for the global film industry - often sought after, and rarely achieved.

In part, this is due to the strict requirements for movies in China. To protect its nascent film industry, China limits the number of foreign films that theaters can show each year.

But foreign films can gain guaranteed access to China's lucrative market by applying to be official U.S.-China co-productions, in which Chinese and American entities work together to create a film.

The sought-after designation means the film will be shown in Chinese movie theaters, and it gives American studios a larger share of the box office take. But in return, the film must typically feature Chinese actors, be at least partially shot in China, and follow China's strict restrictions on content, including censoring any material that portrays the Chinese government, police or army in a negative light.

Very few films have been able to successfully balance these concerns with the demands of both Chinese and American audiences to create a blockbuster that succeeds in both markets - as The Great Wall is attempting to do.

Among the more than one-dozen official co-produced films that the United States and China have made in the past, some have been successful in China - such as Lust, Caution and Skiptrace - but few have registered with American audiences, says Kokas.

Another handful of films have been what Kokas calls "faux productions" - films that were originally designated as U.S.-China co-productions, but that lost that designation due to financial or regulatory difficulties. This group includes some films that performed well in the U.S., such as Iron Man 3, Transformers: Age of Extinction, Cloud Atlas and Looper.

Some Hollywood films manage to do well in China without receiving official co-production status, such as The Martian and Avatar. (Having the Chinese space agency swoop in to save the day, as in the The Martian, never hurts.)

But going forward without official status can be a risky move for Hollywood studios. Chinese officials may decide to give the film a less popular release date at movie theaters, put it head-to-head against other major Western film releases, delay the release of the film so long that many Chinese have already seen pirated versions, or bar the film from the Chinese box office altogether - decisions that can crush a film's profits in China.

Co-productions, which must satisfy Chinese censors as well as commercial motives, can also feel stilted and contrived. One of the only co-produced films that has really succeeded among both Chinese and American audiences thus far, says Kokas, is Kung Fu Panda 3.

But she says its particular winning formula is not one that's easily replicable. As a family film, it didn't run up against censorship restrictions. Subtitles weren't an issue, since the studios created two versions of the animation to match the English and Chinese language tracks. And because the film is animated, the topic of the actors' race did not come up.

But the Chinese and Hollywood studios backing The Great Wall are hoping that their formula will finally crack the code.

The film, backed by Universal Pictures and others, features a large cast of famous Chinese actors, including megastar Andy Lau, actress Jing Tian and boy-band heartthrob Wang Junkai.

It is directed by Zhang Yimou, perhaps China's most famous filmmaker. It prominently features an aspect of China that is also known around the world: the Great Wall. And it is being produced by Legendary Entertainment, a Hollywood studio that was acquired by the Chinese company Dalian Wanda earlier this year, the first time a major American production company has come under Chinese control.

The film was written by Hollywood screenwriters, and it features Western stars Damon, Dafoe and Pedro Pascal, apparently in a bid to attract audiences outside China's borders. It's this aspect that has made the film so controversial in the West, where Hollywood has been increasingly under fire in recent years for racism, both explicit and implicit.

That backlash was led in part by Asian American actress Constance Wu, who called out the film on social media for "perpetuating the racist myth that only a white man can save the world." Others said the choice revealed the assumption that the default American moviegoer is white or only prefers white actors.

There is another less recognized way in which the heroism of Damon's character, a European mercenary who ultimately helps to save China, could be seen as problematic.

Though the details of the film's plot have not been fully revealed, it appears to jar uncomfortably with China's actual history of colonialism, in which the country was conquered, parceled out and impoverished by European armies, a devastating period the Chinese still remember as their "century of humiliation."

Director Zhang Yimou spoke out to defend The Great Wall against charges of whitewashing late last week. "In many ways The Great Wall is the opposite of what is being suggested. For the first time, a film deeply rooted in Chinese culture, with one of the largest Chinese casts ever assembled, is being made at tent pole scale for a world audience."

He added, "Matt Damon is not playing a role that was originally conceived for a Chinese actor."

Others have pointed to an obvious profit motive in the choice, saying that Damon's presence in the film is likely to bring in viewers around the world who wouldn't ordinarily watch a film set in ancient China. Legendary Entertainment did not respond to requests for comment.

PoPing AuYeung, a casting director who has worked on Hollywood and Chinese films for decades, says that Chinese filmmakers do remain concerned about trying to market movies with Chinese leading characters to a global audience.

"They think they will lose the global market if they have Chinese as a lead. But they seem to forget that China is a huge market. A lot of movies flop in the U.S. but make it up in China."

In addition, the strategy of putting a white Hollywood actor at the helm of a movie to broaden its reach can fail too, as Constance Wu pointed out. That's true for Chinese films as well: Chinese studios have paid millions of dollars to stars including Christian Bale, Adrien Brody and John Cusack to appear in mostly Chinese films that ultimately had little success in Western markets.

Inside China, the conversation surrounding the film has been very different. Most Chinese have cheered it, seeing Zhang Yimou's involvement in a big-budget Hollywood film and the prominence of the Great Wall as forces that could advance China's cultural influence abroad.

And now that Legendary Entertainment is owned by Chinese company Dalian Wanda, those in the industry are watching eagerly to see whether China's influence in Hollywood and the global film market will grow.

If The Great Wall is a box office hit, it could serve as a model for future China-U.S. co-productions. If it flops, it will likely leave the industry further confused about how to create a film that appeals to both Chinese and international audiences - and whether such a task can reliably be done.

"I think if The Great Wall is successful, it will signal a new path to Chinese global media power," says Kokas.

"However, I think the initial responses to the trailer signal that actually a lot of Sino-U.S. co-productions may have a lot of success in one market and may not meet expectations in the other."