During an appearance at Wizard World Comic-Con in St. Louis over the weekend, Nathan Fillion teased that he may have a role in this summer's Guardians of the Galaxy. While this is the first we're hearing about his appearance, it shouldn't come as too big a surprise, since he starred in both of Guardians of the Galaxy director James Gunn's previous features (Slither and Super) and worked with Marvel's Joss Whedon on the cult classic TV series Firefly. Take a look at the video below where, at the 38:30 mark, Nathan Fillion makes his surprise revelation, when asked by a fan if he wanted to get a part in Guardians of the Galaxy. Is it at all possible that he will appear for just a brief second as that other intergalactic 'Star-Lord' Captain Mal Reynolds? Anything is possible...

"Wanting to get a part... or maybe did. I'm just saying maybe. Maybe you'll be surprised. Maybe. Check the credits."

Just minutes ago, director James Gunn responded to the actor's revelation over the weekend.

The filmmaker also recently commented on Guardians of the Galaxy's reshoots, where he talks about what they plan on shooting, while teasing a cameo possibility.

"Anything we want, but didnt get, something to make the movie better, cool cameo idea."

While it was believed that the reshoots have already wrapped, Zoe Saldana and Karen Gillan sent out the following tweets earlier today revealing that more shooting is currently happening.

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Nathan Fillion's schedule on ABC's Castle prevents him from taking on a major role in any feature, since he recently said that he only gets two months off per year between seasons. Before Paul Rudd and Michael Douglas signed on to play Scott Lang and Hank Pym in Ant-Man, Nathan Fillion was a popular fan choice to take on either one of those roles, but the actor revealed in an interview with IGN that his work schedule is rather full at the moment.

"I'm pretty booked-up right now as far as work goes and there's so much more going on in the entertainment industry than just, 'Oh, you know who would be great in that?' There's a lot more that comes into play. There's a lot of variables that a fan does not have to concern themselves with. If they want to see a movie and they want that actor, they're not thinking about the variables that come into play. But there are a lot of variables that don't make it a real possibility."

With that being said, it's completely possible that he came on to play a small role during Guardians of the Galaxy's reshoots. Who do you think he will play? Chime in with your thoughts below.