At a promotional event for Riddick, Diesel finally went into more detail about how he ended up negotiating a deal for voice and motion capture work as the comic book character -- and why he had originally met with Marvel.
"What can I say about Groot? I can say something about Marvel," he tells The Hollywood Reporter. "I take my hat off to them for being so creative and thinking outside of the box."
Diesel says that he had originally met with Marvel to launch a fresh IP (intellectual property).
"That was the focus of our conversation — a fresh IP that would come out in 2016 or 2017, and potentially launch the third phase," he tells THR.
But then he went to Comic-Con to promote Riddick. At the annual convention in San Diego in July, he realized that fans didn't want to wait that long to see Diesel as part of the Marvel universe.
"With my schedule, it was almost impossible to imagine I could do anything immediate," says Diesel who will star in the upcoming seventh installment of the Fast & Furious franchise and has several other films in various stages of production.
"I guess after they watched Iron Giant, or whatever, they came up with this idea of taking the strangest Marvel character -- or the strangest Marvel character that's ever hit film -- and thought what I could do with that with motion capture and with my voice," he said.