Say it with us now: Diesel ... is ... Groot!

After months of being attached to the film, without any official confirmation from Marvel Studios or director James Gunn, the "rumors" are now official: Vin Diesel will play a walking, talking tree in "Guardians of the Galaxy," the new Marvel superhero team-up set to hit theaters next summer.

Gunn was first to confirm the news, using Facebook to post a picture of Diesel posing with a Groot model. Marvel confirmed the casting with an announcement of their own, some hours later. As to the question of, well, why did it take so long for Diesel, Marvel and Gunn to confirm the Groot casting? Gunn addressed that mystery as well.

"He was never announced," the director said. "He said he wanted to do it and we said we were talking to him. Everything else was people guessing and thinking they knew what was going to happen."

Gunn added, "I hope this puts to rest all the silly Thanos-Vin stuff which people just seemed to make up out of nothing."

Does this put the "silly Thanos-Vin stuff" to rest, or does this only further fuel that fire? Now that it's official that Diesel is onboard "Guardians of the Galaxy," certainly some fans will take the conspiracy theorizing to the next level — saying that Diesel's casting as Groot is just a cover-up for the actor playing the Infinity Gauntlet-wielding "Avengers" villain.

For now, at least, Diesel is Groot. Click here for much more information on Groot, but the short version is that he's a sentient tree who pals around with a gun-toting space-raccoon named Rocket Raccoon, voiced by Bradley Cooper. The only words that Groot ever says are "I am Groot." It's a valuable use of Diesel's talents.

"Guardians of the Galaxy" hits theaters on August 1, 2014.