Just yesterday Guardians of the Galaxy director James Gunn confirmed that Firefly actor Nathan Fillion would have a cameo in Marvel’s upcoming film, and you won’t believe what he’ll reportedly be playing. (spoilers)

Fans were excited to hear that Castle actor Nathan Fillion would have a “very fun cameo” in Guardians of the Galaxy, but Gunn wouldn’t reveal who the actor is playing. Now we have a report from a reliable source which says he’ll be playing none other than: A dog.

The Schmoes reports, “According to our very reliable source with intimate knowledge of this and the production has spoken exclusively to us about this and we here at Schmoes Know have our answer: Nathan Fillion will be voicing the part of Cosmo, the psychic Russian cosmonaut dog that has appeared in the Guardians of the Galaxy comics.”

So Fillion will be voicing Cosmo, the psychic Russian dog that has appeared in many of the Guardians of the Galaxy comics. While it sounds ridiculous, we think it’s right up Fillion and Gunn’s alley, to put him behind the voice of a talking space dog. Apparently he and Rocket Raccoon have an interesting relationship.

Apparently Nathan Fillion and the film’s director James Gunn are close friends, so they probably concocted this brilliant idea while going over script details for Marvel’s highly anticipated film.

The actor has a massive following due to his many interesting sci-fi roles and Guardians looked like it would have been the perfect film to give the actor a beefy, comedic role. But, we’ll take a cameo as a talking dog in Marvel’s upcoming film featuring a remarkable cast.

Guardians of the Galaxy’s recent trailer gave us some great looks at Chris Pratt and Zoe Saldana, and more importantly, showed us quite a bit more of Bradley Cooper voicing Rocket Raccoon. It looks as though he’ll be quite talkative in the film.

Guardians of the Galaxy’s release date is set for August 1, 2014. Featuring an intergalactic group of Guardians, led by Star-Lord, they make a desperate stand to save the galaxy.

Two-time Academy Award nominee Bradley Cooper voices the machine-gun-wielding Rocket Raccoon and is joined by Vin Diesel as the tree-like Groot, with Zoe Saldana, Chris Pratt, Karen Gillan and Dave Bautista filling out the leading roles.

Woof.