Report: James Gunn favorites Nathan Fillion and Steve Agee join The Suicide Squad

James Gunn is reportedly bringing two returning collaborators in to join his first DC Comics adaptation, The Suicide Squad, including fan-favorite star of Firefly and Castle Nathan Fillion.

Deadline reports that Fillion -- who's worked with Gunn on Super, Slither, and Guardians of the Galaxy in a cameo voice role -- will be joining the new antihero team movie in a role that's still unknown. It's an unconfirmed report at the moment, but Gunn has a history of working certain friends and favorite collaborators into his films wherever he can, so it wouldn't be surprising at all to see Fillion pop up in this one.

Reports of Fillion's involvement come just one day after Deadline also reported that writer/producer/comedian Steve Agee is joining the film as the supervillain King Shark. Agee is also a frequent Gunn collaborator, having appeared in Guardians of the Galaxy Vol. 2, Super, and the Gunn-produced Brightburn earlier this year. As for King Shark ... well, he's a big ol' shark with legs, created by Karl Kesel and Tom Grummet and first appearing in their Superboy stories in 1994. He's become a fan favorite over the years thanks to his appearance in books like Gail Simon's Secret Six run, and recently made his first live-action appearances in The CW's Arrowverse. Now he'll reportedly make the leap to the big screen.

The Suicide Squad was announced as Gunn's next project during the months-long period when Marvel Studios fired him due to years-old tweets dug up by far-right websites. He has since been rehired at Marvel to work on Guardians of the Galaxy Vol. 3, but now The Suicide Squad will come first. The film looks to bring a new tone to the antihero team that first hit the big screen in 2016 under writer/director David Ayer, and as a result we're getting a new version of the time that will unite some of Ayer's cast with Gunn's new one.

Among the reportedly returning stars this time out are Margot Robbie (Harley Quinn), Viola Davis (Amanda Waller), Jai Courtney (Boomerang), and Joel Kinnaman (Rick Flag). They'll be joined by new cast members including Idris Elba, David Dastmalchian (Polka-Dot Man), Flula Borg, and Daniela Melchior (Ratcatcher).

Deadline's reports also reveal that the film is apparently heading into production next month, with a table read on September 11 and a shoot kicking off September 23, so hopefully we'll be hearing more directly from Gunn as the film gets underway. The Suicide Squad is scheduled to hit theaters August 6, 2021, five years and one day after Ayer's film.