One of the after-credit scenes for Guardians of the Galaxy Vol. 2 had Peter Quill (Chris Pratt) walking into Groot's room. Groot has grown up and is now a teenager. The scene was funny but when audiences at D23 and SDCC got a look at Groot from Avengers: Infinity War and he looked very similar to the one from that after credits scene. Cinema Blend also noticed and managed to get a confirmation out of director James Gunn (mostly).
Having seen the Infinity War footage at D23 and Comic-Con, Groot did look very similar to the way he looks in the post-credits scene…
James Gunn: He's exactly the same.
He is exactly the same.
James Gunn: That's exactly the Groot we designed for Infinity War.
So then that scene is set four years after…
James Gunn: Well, basically those are at the same time.
That sounds more or less like a confirmation. The line of questioning came from Gunn being asked about Groot and his age. Was this the first time he's been reborn? Gunn didn't want to say much because these are stories that he wants to tell but he did give us some clues.
Well, you know, it's complicated. I think you have to stick through future movies to find out exactly what the story of Groot is. I get a lot of questions, and the thing I say that bums people out more than anything else is that Baby Groot doesn't have the memories of Adult Groot. But it's complicated! His life is not like our lives… It's his aging, and Groots, where they come from and how they do their thing. It's pretty much worked out in my head, but we've only let out pieces of that.
Groot is not a person so he ages differently from the way we do, of course. Groot has become a huge character in Guardians so expect to see more of him in the third installment.
Guardians of the Galaxy Vol. 2 will be released digitally in HD, 4K Ultra HD, and Disney Movies Anywhere on August 8th and physically on 4K Ultra HD, Blu-ray, and DVD August 22nd.