While there were many naysayers who thought that last year's Guardians of the Galaxy would be Marvel's first box office flop, they were dead wrong. Guardians of the Galaxy went on to become one of the biggest hits of 2014, and now the long wait for Guardians of the Galaxy Vol. 2 begins, with the studio setting a May 5, 2017 release date for the sequel. While no cast members have been confirmed, most have assumed the the main cast will be returning, but, in case you aren't convinced yet, director James Gunn revealed on his Facebook page today that Vin Diesel is coming back to voice Groot in Guardians of the Galaxy 2.

The director confirmed this information when a fan mistakenly asked if Vin Diesel was coming back for Guardians of the Galaxy 3, with some believing that the filmmaker had actually confirmed GOTG 3, before Guardians of the Galaxy 2 even started shooting. It was quickly clarified that the fan actually meant Guardians of the Galaxy Vol. 2. Still, Vin Diesel has a whopping three words ("I am Groot"), which they likely recorded numerous times on the first film. And, since the actor doesn't perform the motion-capture for this massive tree creature, some may wonder if there is even much use for Vin Diesel in the sequel. But there are a number of reasons why he would be needed to come back.

It seems unlikely that Groot's vocabulary will expand in Guardians of the Galaxy Vol. 2, but this creature and his miscreant cohorts Star-Lord (Chris Pratt), Gamora (Zoe Saldana), Drax (Dave Bautista) and Rocket (Bradley Cooper) will be on an entirely new adventure. While Vin Diesel's Groot won't likely say more than his usual three-word line, the way he says it, and the way he reacts to his new surroundings, will certainly change. Who knows, perhaps James Gunn will throw us another surprise, like the "We are Groot" line at the end of Guardians of the Galaxy.

RELATED: Chris Pratt Auditioned for Captain America Before Landing Star-Lord

Groot could easily be compared to Hodor (Kristian Nairn) from Game of Thrones, only Hodor's vocabulary is even more limited. While that character only has one line ("Hodor") he says throughout the series, the way he says his own name, at certain times, keys us in to how he's really feeling, in spite of his limited vocabulary. It will be interesting to see if James Gunn will employ a similar tactic with Groot in the sequel. All we know about the follow-up so far is that the filmmaker recently completed the script, with the project set to begin early next year.

Now that we know Vin Diesel is coming back to voice Groot, there is still another burning question: will we see dancing Baby Groot or full-grown Groot in Guardians of the Galaxy Vol. 2? Or will it be a combination of the two? Baby Groot became a cultural sensation on its own, apart from the success of the movie, so it wouldn't be surprising it we saw this tiny dancing tree at least once in the sequel.