Standing before thousands of rabid fans in Comic-Con's giant Hall H is enough to make your hair fall out. But that's not why Karen Gillan showed up bald to the Marvel panel on Saturday.

Well, technically, Gillan – the "Doctor Who" star who plays the super-villainous space pirate Nebula in Marvel's upcoming "Guardians of the Galaxy" movie – showed up to the panel in a wig. And as far as the audience was concerned, her hair appeared as it always did: long and red.

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But when it came Gillan's turn to speak, panel moderator Chris Hardwick (aka the Nerdist) lofted the Scottish actress this easy setup: "Isn't Nebula bald?"

"Yeah, she is. And I might have done something a little bit crazy," responded Gillan, who proceeded to pull the wig off and reveal her shiny bald dome to the cheering crowd.

As screaming crowds can sometimes make one do, Gillan got a little crazier and threw her wig into the audience – though she quickly realized that was a mistake. "I need that back!" She shouted.

Ever quick with a comeback, Hardwick quipped, "You do NOT want to give your wig to people at Comic-Con."

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Looking at the "Guardians of the Galaxy" panel, it might seem that baldness is written into the script. No less than four actors showed up with fully or partially exposed domes: Michael Rooker (Yondu), Dave Bautista (Drax the Destroyer), and Djimon Hounsou (Korath) all joined Gillan in bald-solidarity. (See the photo gallery below).

Maybe there's just something in the hair?

We'll find out when "Guardians of the Galaxy" opens on August 1, 2014.