When asked about taking on the role, which came as somewhat of a surprise to his fans, the actor revealed he was interested in playing a role that wasn't an obvious choice for him.
"I'm an actor. I can do whatever the ... I want. As an actor, not everything has to be the most obvious choice. And sometimes, the best thing you can do - as far as Steven Spielberg and his advice - is to defy expectations. So if everybody thinks you're going to go for this one thing and you flip it entirely and go for the strangest Marvel character, it's interesting. And when something is interesting, it's inspiring."
The actor also teased why he posted that particular image of Groot over the weekend.
"I get inspired by things. So if somebody sends me a book of conceptual art that's the best character design work I've ever seen - I'm not kidding, I see that and I want to be a little cryptic and I want to say something positive. Even if it's as cryptic as an old, dated image of a character."
He also spoke about how open he is with his fans on social media platforms, and if that caused any friction with Marvel and their secretive ways.
"The last thing they are is mad. I'm pretty open, but I have been secretive about this. I went to Comic-Con and I got blasted while I was on the Hall H panel for Riddick. Someone asked a Marvel question. I couldn't say anything because of that secrecy."
"That's the thing - I'm so busy. The audience wanted Vin and Marvel, Vin and Marvel. But I'm too busy to do a six-month role. So what Marvel came up with was really interesting. ... I am watching a social wave influence and in some ways guide their thinking."
Guardians of the Galaxy was released August 1st, 2014 and stars Chris Pratt, Zoe Saldana, Dave Bautista, Vin Diesel, Bradley Cooper, Lee Pace, Michael Rooker, Karen Gillan. The film is directed by James Gunn.