Rupert Friend and Stuart Martin have joined the cast of 'Rebel Moon'.

The pair are both set to play antagonists in the new Netflix sci-fi epic that will be directed by Zack Snyder.

Sofia Boutella is leading the ensemble cast for the movie and will be joined by Charlie Hunnam, Djimon Hounsou, Doona Bae and Ray Fisher.

The flick is set in a peaceful colony on the edge of a galaxy that is threatened by the armies of a tyrannical regent named Belisarius. The desperate colonists dispatch a young woman (Boutella) with a mysterious past to seek out warriors from neighbouring planets to help them make a stand.

Rupert will play the story's main villain, a man who leads the armies and squares off against Boutella's alter ego.

Martin's character details are not yet known but he is also said to be villainous.

Production on the movie is scheduled to begin in April and last until November. As well as directing, Snyder co-wrote the script with Shay Hatten and Kurt Johnstad.

Zack will be producing with his producing partner and wife Deborah Snyder and Wesley Coller via the trio's The Stone Quarry production banner. Eric Newman is also producing for Grand Electric.

Snyder previously explained that the movie is a passion project because of his interest in sci-fi and hopes that the film marks the launch of a franchise.

The 56-year-old director said: "This is me growing up as an Akira Kurosawa fan, a 'Star Wars' fan.

"It’s my love of sci-fi and a giant adventure. My hope is that this also becomes a massive IP and a universe that can be built out."