Watch: Matt Damon in first trailer for Zhang Yimou's Great Wall

Acclaimed Chinese film director and national treasure Zhang Yimou has outed himself as a Matt Damon sympathiser after a trailer was released for his upcoming sci-fi epic, The Great Wall.

Damon takes top-billing in Zhang's latest and first entirely English-language feature, with the trailer shedding no light on how the star came to be on The Great Wall of China in the Northern Song dynasty some 1,000 years ago. 

It does, however, explain Damon's business on The Wall, which in a brutal metaphorical sideswipe at Mongols everywhere, is to defend the Middle Kingdom against a swath of rabid CGI beasts in a colourful, swashbuckling re-imagining of The Wall's historical functionality.

The Great Wall is due to drop in China December this year, having cost 135 million USD to make. With Damon - who appears to utter more words in this trailer than in the entirety of Jason Bourne - being one of the most bankable stars in Hollywood and the rampant growth of China's cinema market at the moment, that looks to be a solid investment.

Here's the trailer:

However, the teaser has stirred controversy over the selection of Damon in a role that some have claimed should not have been given to a caucasian male, with The Guardian reporting a 'chorus of outrage' over the trailer.

While acknowledging that the apparent presence of mythical beasts attacking the Wall suggests that the film isn't necessarily aiming for factual accuracy, critics have taken issue with what they see as the movie perpetuating the idea that only a white man can save the day.

Comments from the Weiborati have been overwhelmingly positive. Though a few have reposted the BBC's article on the 'whitewashing' controversy, it's been generally met with bemusement and any discussion of casting has so far centred on the roles of cherub-faced pop stars Wang Junkai of TFBoys and Lu Han ('Lu Ge') of EXO rather than that of Damon. Here are a few of the more critical Weibo comments on the trailer:

@heixiang: 'To be honest, this casting is really odd. Lu Han's style is totally different'

@haohaonvzishigesha: 'The casting seems a bit awkward...'

@allenfw (in response to the above message): 'It's all down to commercial considerations'

@wotemacaizhidaoweibokeyigaiming: 'What's with Matt Damon? What's with these multi-coloured sets of armour?'

@zhangxiuzhe: 'Ignorant foreigners. There were always white people around the Great Wall during ancient times'

For his part, Zhang has spoken of the movie as 'an English-language film and a Hollywood blockbuster [...] using Hollywood filmmaking to introduce Chinese culture'.