How Bruce Lee, Chow Yun-fat inspired Donnie Yen's character in 'John Wick 4'

Donnie Yen found intriguing ways for his character to mirror John Wick. Photo: Handout

John Wick 4's not-so-secret weapon is the biggest action star to join the franchise: Hong Kong cinema icon Donnie Yen.

As the blind assassin Caine, another old friend and antagonist of Wick's maybe-final chapter, he fills the screen with cool wit and lethal grace – a deadly Fred Astaire with a bladed walking stick who steals the movie each time he glides onscreen.