News of Fillion's casting in Gunn's version of the DC anti-hero group circulated last year, but just who he is playing remains a mystery. Gunn previously stated Fillion is not Arm-Fall-Off-Boy during an Instagram Q&A.

Fillion also assured Shaw he was not playing that character.

"That was never a comic I really dived into, so I didn't really know who that was that they were talking about, and it certainly wasn't the name I was reading in the script," Fillion said. "So, I just said, 'Yeah, yeah, go for it. Whatever you guys think is great, so long as you're not asking—' it's so secret. It's so super, duper secret."

He continued, "I'm the worst liar. I couldn't play poker to save my life," referring to his hopes no one asks him directly about his character.

Warner Bros.' The Suicide Squad is set to arrive Aug. 6, 2021, in theaters.

Watch Fillion talk about the film below.