Donnie Yen boards John Wick 4

Donnie Yen has joined the cast of 'John Wick 4'.

The Hong Kong martial artist and actor - who previously appeared in 'Rogue One: A Star Wars Story' and the 'Ip Man' franchise - is set to play an old friend of Keanu Reeves' titular assassin alter ego in the fourth instalment of the blockbuster neo-noir action-thriller franchise.

The pair have a lot in common, including mutual enemies.

On casting the 'Mulan' star, director Chad Stahelski said in a statement: "We are very lucky to have Donnie Yen join the franchise. I am looking forward to working with him in this exciting new role."

Donnie's casting comes days after it was revealed Rina Sawayama will maker her feature film acting debut alongside the star-studded cast.

The 'Chosen Family' singer was hailed an "incredible talent" by the director, though details of her role are being kept under wraps.

Chad said: “I’m so glad to have Rina on board to make her feature film debut in 'John Wick: Chapter 4'. She’s an incredible talent who’ll bring so much to the film.”

Production on the movie - which is based on a script by Shay Hatten and Michael Finch - takes place this summer, with filming planned in France, Germany, and Japan.

It was previously confirmed that the fourth and fifth movies in the series would be filmed back-to-back, but Chad revealed that he was prioritising the fourth instalment.

The 52-year-old filmmaker explained: "The way Keanu and I approach it with our writing team is, 'Look, we have ideas, but it's not like I'm working with two sets of writers on two movies.'

"We're going to write a really good number four. If a really good number four feels solid to Keanu and I, we'll make that one. That doesn't mean we won't plan on a five or start writing five, but we want to make sure we have a solid story."