James Badge Dale, who plays Coldblood, claimed that Ben Kingsley's Mandarin is in reality a servant of Pearce's Aldrich Killan.
"Ben Kingsley is the mouthpiece," Dale told Showbiz411. "Guy Pearce is the brain. I'm the muscle."
Pearce was previously expected to play the main villain of the movie, before he described his role as "cameo stuff". Kingsley has been assumed to be the villainous mastermind of the Marvel Studios film.
Samuel L Jackson recently revealed that neither his Nick Fury nor any of the other Avengers would be making an appearance in the movie.
Iron Man 3 will arrive in UK cinemas on April 26, 2013, following in the US on May 3.
Watch the film's first trailer below:
Photo gallery - Iron Man 3: