Guardians of the Galaxy is arguably the biggest wild card among the confirmed Marvel Movie Universe (MMU) installments leading up to The Avengers 2 in 2015; it's even more out there (literally) than Marvel's initial foray into the cosmic superhero genre with Thor. Whereas that film features main characters who are, at least, humanoid in appearance, the Guardians include a gun-wielding raccoon who likes to wear rocket shoes - among other curious alien life forms.

Marvel has decided to pair the unusual Guardians of the Galaxy property with an equally-unique filmmaker in James Gunn, who has been given the official stamp of approval from MMU "Phase 2" overseer and Avengers director, Joss Whedon. Gunn and Whedon's frequent collaborator, Nathan Fillion, seems an obvious choice to come aboard as one of the Guardians after Marvel approached Gunn. However, we haven't heard anything from the Firefly and Castle fan-fave actor on the subject - until now.

Fillion has been attending the Toronto International Film Festival over the past week, where he's been picking up raves for his supporting role in Whedon's home-made take (literally) on Much Ado About Nothing. MTV managed to catch up with the actor and ask him about Guardians of the Galaxy, but Fillion appeared to be wary of the prospect:

"I'm very busy right now with a job that I'm grateful for. I've made a commitment [to 'Castle'] and I have to see it through. And I'm really happy to."

Bear in mind, there are a few factors that Fillion might be taking into account here. For one, Guardians most likely will not start shooting until after Captain America: The Winter Soldier gets underway next March. Moreover, Marvel tends to space out production schedules to avoid excessive overlap; hence, Guardians might not actually begin filming until May or June next year, at the earliest. By that time, Fillion should be done working on Castle for the fifth season (or permanently, if the show is not renewed).

The actor has been rumored as a prospective for Edgar Wright's Ant-Man movie for years, but recent rumors point to that film possibly beginning production after Thor: The Dark World (but before Winter Soldier); if that's true, we can discount the possibility that Fillion is secretly passing over Guardians for Ant-Man. Besides, the chance to re-team with Gunn - as well as Whedon, to a lesser degree - seems the more obvious route for Fillion, especially since many expect the role of the Guardians' leader, Star-Lord, will be a perfect fit for the actor.

Guardians of the Galaxy's Star-Lord

While none of this speculation guarantees that Fillion will ultimately be able to find time for Guardians, the actor is nonetheless lending his support to Gunn's vision for the film (as Whedon did earlier this week):

"We had dinner the other night and he told me all about ['Guardians of the Galaxy'], before everyone found out. I was on the inside on that one. Over some toro, tuna belly, we discussed how excited he is, how nervous he is, but how he wanted it very badly. He wanted it very badly. I think it's in very capable hands. It's in the right hands. Having worked with the man, I know what he's capable of."

What role in the MMU would you like to see Nathan Fillion take on, assuming he can find the time? Let us know in the comments section.

As for the confirmed Marvel "Phase 2" release schedule: Iron Man 3 hits theaters on May 3rd, 2013, Thor: The Dark World on November 8th, 2013, Captain America: The Winter Soldier on April 4th, 2014, Guardians of the Galaxy on August 1st, 2014, and The Avengers 2 on May 1st, 2015.

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Source: MTV