Which Geek-Favorite Actor May Have A Cameo In Guardians Of The Galaxy?

Some filmmakers develop a troupe of people they work with over and over again because of talent, sometimes it's because people just get along well, and sometimes it's both. Judging from the growth of a particular filmmaker's influence on the Marvel Cinematic Universe, a lot of people seem to respect the work of and really get along with Joss Whedon. For this reason, it's not a huge surprise that, while the director is working with the megastars of Avengers: Age Of Ultron, other past Whedon collaborators have been finding their way into the comic book world. Could one of them be an old fan favorite? Possible spoilers from here on out.

At the recent St. Louis Comic-Con there was a special panel reuniting the cast of the Whedon-created television series Firefly. During the event, a fan asked Nathan Fillion a question about James Gunn's Guardians Of The Galaxy... and his answer was very intersting:

In case you missed it, he says,

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

In addition to his Whedon's credits, Fillion, you may recall, was the leading man in Gunn's breakout directorial effort, the very funny horror film Slither. Fillion also popped up in a brief role in Gunn's last feature, Super, and his goof-off web series PG Porn:

It makes sense that the Castle actor would hook up again with the gang, especially considering that, in general blockbuster fashion, the production recently underwent some late reshoots.

Fillion's the sort of guy that's been linked to superhero roles for years and years. Fans have long campaigned for him to play just about every costumed crimefighter, and for a long time he was considered a favorite by many to star in 2011's Green Lantern. Instead he has settled for voicing the character in a series of DC Comics Animated films, as his role in the aforementioned ABC series kind of holds him back from big screen leading man stardom. By the time he struggled to squeeze into some extra-tight khaki shorts for Percy Jackson: Sea Of Monsters, it seemed clear that getting syndicated TV residuals was probably a sweeter deal than having to slug around in some blockbusters.

If Fillion is telling the truth, then who could he be playing in a Guardians of the Galaxy? Will he be playing an alien under heavy makeup, which is why we will need to look at the credits to see if it's him? Or is he referring to one of Marvel Studios' famous end credits sequences? It's been said by the folks at Marvel that the Guardians arm of the Cinematic Universe will start out with only light ties to everything else going on, so it might not be anything other than a silly joke. But, you know... c'mon, he's probably Thanos.