Of all the characters we could see muscle-y Vin Diesel possibly portraying, talking tree is not one of them, but hey—at least he's still surprising us. According to Deadline, Diesel in talks to voice Groot, an extraterrestrial plant creature, in Marvel's upcoming Guardians of the Galaxy film adaptation.
None of this has been officially confirmed, of course, but there's a substantial amount of proof that this deal will go through, mostly thanks to Diesel himself. Early last month, Diesel posted on his Facebook page about a mystery role, saying, "Marvel meeting today. … Only the people in the room can tell you what was discussed. … P.s. Thanks to Our page, for pushing to make it happen… you know I get tunnel vision with my work… and after that meeting today… wow!"
Then yesterday, in what is perhaps the most obvious indicator that Diesel will be joining the film, Diesel posted a captionless picture of Groot and made it his cover photo, before taking it down a few hours later. So, either he really likes Groot, or he's just bad at keeping secrets.
In addition to (possibly) Diesel, the Guardians of the Galaxy cast is pretty star-studded: Karen Gillan, Benicio Del Toro, Lee Pace, The Walking Dead star Michael Rooker, Chris Pratt, Zoe Saldana, Dave Bautista, John C. Reilly, and Glenn Close are all confirmed to star—and that's just to name a few.