The name on everybody's lips in the Marvel Cinematic Universe is Thanos. Ever since the epically powerful comic book bad guy made an appearance in the post-credits scene for 'The Avengers,' thereby confirming his presence in future movies, inquiring minds have been dying to know which actor will portray him on the big screen. According to Marvel Studios head Kevin Feige, an actor has already been cast, but he doesn't plan on spoiling the big reveal just yet.

In an interview published in the latest issue of Empire magazine (shown via CBM), Feige revealed that, yes, "there is an actor" who'll portray Thanos, and he'll be making a physical appearance in the sci-fi space opera 'Guardians of the Galaxy,' which stars Chris Pratt, Zoe Saldana, Dave Bautista, Vin Diesel and Bradley Cooper. But (and this is a big but) Feige continued, "I'm not sure we want to announce it yet."

Previously, 'Guardians' director James Gunn teased that, while Benicio Del Toro's The Collector, Karen Gillan's Nebula, Michael Rooker's Yondu, Djimon Hounsou's Korath and Lee Pace's Ronan the Accuser would all be the primary antagonists in 'Guardians,' Thanos would be the metaphorical puppet master pulling all the strings. But who will be playing the big baddie himself?

While this is all speculation, our money is on either Benicio Del Toro or Vin Diesel. Although announced as The Collector, Del Toro's Marvel contract includes multiple movies, and from what we know of The Collector, it doesn't seem like he'll be continuing on. Given how eager he was to receive the Aether at the end of 'Thor: The Dark World,' proclaiming, "One down..." The Collector might just be one of a disguise of Thanos.

That said, there's also a good chance Diesel could be a match. Aside from having the build and the voice to pull off one of the most crucial and menacing villains in the Marvel universe, he also teased big things to come between him and Marvel Studios beyond the scope of 'Guardians of the Galaxy.' While it's great to hear him voicing Groot, it does seem suspicious that Marvel would hire such a star-powered actor to repeat "I Am Groot" over and over.

Speculation aside, the events of 'Guardians of the Galaxy' (and the potential 'Guardians of the Galaxy 2') have direct ties to what happens in 'The Avengers 3,' which is when we're assuming we'll finally get to see Thanos make his grand entrance -- and not just his menacing profile.

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