In the Marvel Cinematic Universe, Thor, the God of Thunder and the Hulk, might have many things in common, from their massive strength to their well-placed senses of humor and their proportionally muted rage. Thor Odinson and Bruce Banner are among the Avengers’ more robust fighters, and their shared qualities are a big part of what made them a great team in Thor: Ragnarok.Mark Ruffalo, who plays the Hulk in the Marvel Cinematic Universe, shared a new behind-the-scenes photo from the set of Avengers: Endgame. Here, Ruffalo switches out his usual trimmed coif for what appears to be a wig with long, dark locks, and Chris Hemsworth, who plays Thor, shares his uncharacteristic look.RELATED: Avengers: Endgame - Chris Evans Shares Video From the Set

Since neither one of the actors wore their hair in that style in Endgame, it's not entirely clear if that's their hair or if they're borrowing someone else's wig.

The hair bears a passing resemblance to the hair of Michael Douglas' young Hank Pym in the film's time-traveling sequences. Given the way the hair pieces are styled, there's a good chance they belong to a character who's not in the film's present day, even if it's not Pym.

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Directed by Joe and Anthony Russo, Avengers: Endgame stars Robert Downey Jr. as Iron Man, Chris Evans as Captain America, Mark Ruffalo as Bruce Banner, Chris Hemsworth as Thor, Scarlett Johansson as Black Widow, Jeremy Renner as Hawkeye, Brie Larson as Captain Marvel, Paul Rudd as Ant-Man, Don Cheadle as War Machine, Karen Gillan as Nebula, Danai Gurira as Okoye and Bradley Cooper as Rocket, with Gwyneth Paltrow Pepper Potts, Jon Favreau as Happy Hogan, Benedict Wong as Wong, Tessa Thompson as Valkyrie and Josh Brolin as Thanos. The film is in theaters now.