Luc Besson, French filmmaker. [Photo provided to China Daily]

Wu has more than 25.3 million followers on Sina Weibo, China's answer to Twitter, but his critics have highlighted his poor performance in the Chinese movies Mr Six and The Mermaid.

Besson disagrees. He says the casting of Wu in Valerian was not to exploit any of the pop star's commercial potential.

"Sometimes, when you see a Chinese actor in an American film, you will say they put the Chinese actor for the Chinese market. Most of the time, it's true," he adds.

He says the international space station needed a Chinese actor because it's set in the future. Besson says he didn't know Wu was that popular.

"Rihanna was there. No one screamed for her," he says of a filming set where female fans wanted Wu's attention.

As one of France's best-known directors, Besson says he aspires to rival Hollywood.

"I'm a big fan of international cinema ... I love all kinds of films ... seeing Chinese films, we have learned a lot about China," he says.

Besson says he believes diversity is key to cinematic art.

"Sometimes, it's difficult for local Chinese films or very French movies to go around the world. But they are specific and unique."