Once Upon a Time in China
In 1990s, Mok replaced Yuen Biao, after Yuen declined to reprise his role after the first film was finished. Mok played Leung Foon in four Once Upon a Time in China movies they were: "Once Upon a Time in China II", "III", "IV" and "V" alongside Jet Li, Rosamund Kwan and Vincent Zhao. After Once Upon a Time in China V, Mok didn't appear in the sixth sequel and nobody will replacing him.