Vin Diesel has remained tight-lipped about his rumoured role in Marvel's Guardians Of The Galaxy, saying he wants to "defy expectations".
There is speculation that the Fast And Furious star is to voice tree warrior Groot in the upcoming movie, after he posted a picture of Groot on Facebook.
He laughed off the buzz, telling the Los Angeles Times: "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."
The 46-year-old said Marvel Studios don't mind his social media teasing, adding: "The last thing they are is mad."
Although he hasn't confirmed his Guardians role, Vin - whose real name is Mark Sinclair - said the studio offered him an "interesting" alternative to a full-time commitment.
He revealed: "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.
"The audience wants Marvel and I to do something, and I don't know why it's so important. For six months, I wasn't able to answer this growing request."
Vin, who next stars in Riddick, added cryptically: "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."
Zoe Saldana, John C Reilly and Glenn Close will star in Guardians Of The Galaxy, which has started shooting in London in time for a release in summer 2014.