Guardians of the Galaxy Director James Gunn Confirms Nathan Fillion Cameo

At the time it was our understanding that both Gunn and Fillion had hinted at a cameo by Fillion in the film, but that it was not confirmed.

Well, now it is. When a fan told him that a denial is just what filmmakers do when they want to throw fans off the scent to maintain a surprise, Gunn rejected that theory; a second fan asked point blank whether there was a cameo, and Gunn confirmed that there will be:

Of course, “a small, fun cameo” could be any number of things, but since Fillion is often fan-cast in every superhero movie, since Guardians is shaping up to be a big hit with franchise potential and since Castle seems to be nearing its end, it seems likely Fillion’s role will be small enough, and/or covered in enough makeup, that he could plausibly return for a Marvel role down the line.

Popular fan theories are that he will voice Cosmo, the Russian dog who lives at Knowhere in Dan Abnett and Andy Lanning’s Guardians of the Galaxy comics, or that he will make an uncredited appearance as Mal Reynolds, his character from Joss Whedon’s Firefly and Serenity, whom Fillion’s Castle character has cosplayed in the past.