When actor Hu Jun received the call inviting him to play the role of the musician in the film, he says he was shocked. Most of Hu's best-known screen characters are muscular heroes such as the legendary Qiao Feng in the martial arts TV series Demi-Gods and Semi-Devils.

But the producer Jonathan Shen soon shook off his concerns.

"Hu was born into a musical family. He learned to play the violin when he was young," says Shen, during a Beijing preview event on Monday.

The film is inspired from a speech made by President Xi Jinping during his visit to Kazakhstan in 2013, Shen says.