Jason Momoa backed his co-star Ray Fisher as he alleged “serious stuff went down” during the reshoots for Justice League.

Back in July, the 33-year-old actor, who played Victor Stone/Cyborg in the Warner Bros. blockbuster, accused director Joss Whedon, and producers Geoff Johns and Jon Berg, of “abusive” and “unprofessional” behaviour while filming the 2017 movie.

The star-studded cast, including Momoa, Fisher, Gal Gadot, Ben Affleck, Henry Cavill and Ezra Miller, had to take part in lengthy reshoots after original Justice League director Zack Snyder exited the movie due to a family bereavement, and Whedon took over.

And the Aquaman star has now shed light on some of the alleged unprofessional behaviour on the set, and claimed in an Instagram post that he and his castmates were treated in a “s**tty way” by Warner Bros, and “serious stuff went down”.

“THIS S**T HAS TO STOP AND NEEDS TO BE LOOKED AT @ray8fisher AND EVERYONE ELSE WHO EXPERIENCED WHAT HAPPEN UNDER THE WATCH OF @wbpictures NEEDS PROPER INVESTIGATION,” Momoa wrote alongside a snap of him and Fisher laughing during a Comic-Con event.

He then went on to slam film bosses for falsely announcing he was in talks to voice Frosty the Snowman in an upcoming film – that was to be produced by Berg and Johns – on the same day that Fisher went public with his allegations.

“I just think it’s fked up that people released a fake Frosty announcement without my permission to try to distract from Ray Fisher speaking up about the stty way we were treated on Justice League reshoots,” he continued.

“Serious stuff went down. It needs to be investigated and people need to be held accountable. #IStandWithRayFisher. aloha j,” Momoa added.