 Both of the main actors, Pierre-Matthieu Vital and Qilun Gao, are indirect friends of the film's director, Simon Chung.Vital, who plays Luke, is from France, but lives and works in Guangzhou and regularly visits Hong Kong, where he first met Simon Chung.Vital is not a fluent speaker of Mandarin Chinese, and so Chung had to help train him to speak his lines.