Last week, a rumor surfaced that action icon Sylvester Stallone may have secretly joined the cast of Marvel's highly-anticipated sequel Guardians of the Galaxy Vol. 2, after the actor was spotted leaving the same hotel the cast was staying at, while holding a script. The studio never confirmed that the actor had been cast, but it sparked plenty of speculation about who he may be playing, if the actor actually has signed on. Today we have a new report from On Location Vacations, with a source claiming that the actor has been spotted on the set. There may be potential SPOILERS below, so read on at your own risk.

The site confirmed that Sylvester Stallone has been spotted on the Atlanta set, and while the source doesn't have any information about the character he's playing, the actor is reportedly wearing a costume that is rather familiar. This tipster said that his costume is "quite similar to Judge Dredd." Of course, the actor suited up as Judge Dredd in the 1995 movie adaptation, but it seems rather impossible that he will be playing Dredd, since Marvel does not hold the film rights to this character, originally published by Britians Rebellion Developments. While the character would show up in a few DC Comics titles in the 90s, around the time of the original movie's release, which was distributed by Disney owned Buena Vista Pictures, Warner Bros. and DC don't own the rights at this time either. The reboot released in 2012 was distributed by Lionsgate, and while they have no plans for a sequel, they are believed to still own the rights.

Still, there are a few other possibilities for who the actor might be playing. Some have speculated that he could be playing a member of the Nova Corps, since their costumes do share similarities with Judge Dredd, while other claim that he could be a Kree Accuser. The initial report claimed that Sylvester Stallone wouldn't have much more than a cameo role in this superhero sequel, so whoever he's playing, he may not be on the big screen for too long. It also isn't known if this mystery character will be interacting with any of the actual Guardians or not.

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The film marks the return of the original Guardians including Chris Pratt as Peter Quill/Star-Lord; Zoe Saldana as Gamora; Dave Bautista as Drax; Vin Diesel as the voice of Groot; Bradley Cooper as the voice of Rocket; Michael Rooker as Yondu; Karen Gillan as Nebula; and Sean Gunn as Kraglin. New cast members include Pom Klementieff (Oldboy), Elizabeth Debicki (The Great Gatsby, Everest), Chris Sullivan (The Knick, The Drop) and Kurt Russell (The Hateful Eight, Furious 7). James Gunn directs the sequel from his own screenplay.

Set to the all-new sonic backdrop of Awesome Mixtape #2, Guardians of the Galaxy Vol. 2 continues the team's adventures as they unravel the mystery of Peter Quill's true parentage. Guardians of the Galaxy Vol. 2 is produced by Marvel Studios' president, Kevin Feige, with Louis D'Esposito, Victoria Alonso, Jonathan Schwartz, Nikolas Korda and Stan Lee serving as executive producers. In related news, writer-director James Gunn shared a photo with the cast in rehearsals on his|Twitter page earlier today, which you can check out below. Do you have any theories about who Sylvester Stallone could be playing in Guardians of the Galaxy Vol. 2?