James Gunn has announced that Sylvester Stallone has been cast in a mystery role for the upcoming DC movie The Suicide Squad. Taking to Instagram, Gunn posted a photo of himself alongside Stallone, revealing to his followers that the famous Rocky and Rambo star will appear in the movie.

"Always love working with my friend @officialslystallone & our work today on #TheSuicideSquad was no exception," James Gunn writes in the caption. "Despite Sly being an iconic movie star, most people still don't have any idea what an amazing actor this guy is."

RELATED: HBO Max's The Suicide Squad Spinoff Series Gets Robert Patrick, Jennifer Holland & More

In an Instagram post of his own, Sylvester Stallone also addressed his casting with a message of support for Gunn. "Working with this incredible Director on this astounding project has made this an amazing year. I am a very lucky man to be surrounded by such talent!" Stallone said.

The Suicide Squad is more of a reboot than a sequel to David Ayer's 2016 take on the movie, but there are some returning characters. We know that Margot Robbie (Harley Quinn), Jai Courtney (Captain Boomerang), Viola Davis (Amanda Waller), and Joel Kinnaman (Rick Flagg) will all be back. Meanwhile, new additions to the cast include Idris Elba (Bloodsport), John Cena (Peacemaker), Peter Capaldi (The Thinker), David Dastmalchian (Polka-Dot Man), and Michael Rooker (Savant).

As of now, there's no word yet on which character Stallone could be playing in the movie. Deadline reports that there's "speculation" he could be the voice of King Shark, a shark-human hybrid supervillain played by Steve Agee. That seems possible as Agee is also playing the role of Belle Reve penitentiary warden John Economos. Of course, if Stallone's role in The Suicide Squad is a voice role, fans will certainly know it when they hear it as soon as the character speaks on-screen.

This won't be the first time Gunn and Stallone have worked together. In Guardians of the Galaxy Vol. 2, Stallone appeared as Stakar Ogord, a Ravager embroiled in a feud with Yondu (Michael Rooker). At the time, Gunn also stressed the importance of this role in the Marvel Cinematic Universe, noting that it was their plan "to see more of Stallone" in future MCU movies. It's still unclear if Stakar will return in Guardians of the Galaxy Vol. 3, but we'll find out soon enough, as Gunn will begin work on the anticipated sequel after he is finished with The Suicide Squad.

Meanwhile, Stallone fans have also gotten to see the legendary actor revisit some of his most famous roles in recent years. He reprised the role of Rocky Balboa in 2018's Creed II, and he has expressed some interest in making another Rocky movie. Last year, he played John Rambo in the action thriller Rambo: Last Blood and appeared in the third installment of the Escape Plan series. Stallone will also star in next year's Samaritan, a movie about a former superhero believed to be missing who is discovered by a young boy. It will release in theaters on June 4, 2021, and The Suicide Squad will be released on Aug. 6, 2021. This news comes to us from Deadline.

Jeremy Dick at Movieweb
Jeremy Dick