While rumored since filming began, Marvel has finally confirmed Vin Diesel will be voicing Groot in director James Gunn’s Guardians of the Galaxy. In addition, Diesel posted a picture of himself posing with the tree-like Groot, and James Gunn also offered his thoughts on Diesel being involved in the project.

“Yep it is completely official. AND he’s amazing. I never knew someone could say I AM GROOT so many different ways and with such feeling (and that sounds like I’m kidding but I’m not!)”

Hit the jump to check out the image along with Marvel’s press release. The film stars Chris Pratt, Zoe Saldana, Dave Bautista, Vin Diesel, Bradley Cooper, Lee Pace, Karen Gillan, John C. Reilly, Glenn Close, Michael Rooker, Djimon Hounsou, Peter Serafinowicz, and Benicio Del Toro. Guardians of the Galaxy opens August 1, 2014.

Here’s what Gunn had to say about Diesel (via Twitter), followed by the image (via Facebook):

James Gunn ‏@JamesGunn Vin Diesel is a super awesome dude. I can’t tell you how much I like this guy. http://www.whosay.com/l/tGe7t8g