He — is — Groot!

Actor Vin Diesel has posted a video on his Facebook page showing himself walking around on stilts on the set of Fast & Furious 7 in preparation to play the sentient tree-creature Groot in Marvel's Guardians of the Galaxy.

In the video, Diesel confirms he has just one line of dialogue in director James Gunn's space adventure — the much-anticipated "I am Groot," one assumes — but the simple dialogue isn't a letdown for the actor.

"My father taught me there are no small roles, only small actors," he says. "I have one line in the movie, but that doesn't mean anything. I'm still going to make it the best thing I possibly can. Even if it means taking Andy Serkis to a whole other level, which is what we wanna do with out motion capture."

Watch Diesel do the Groot in the video below, and look out for one of the actor's Guardians co-stars as well: