With "The Avengers" just days away from opening, Marvel is now focusing on building the cast of the upcoming "Iron Man 3."

Guy Pearce is in talks to join Robert Downey Jr., Gwyneth Paltrow and Ben Kingsley in the Marvel sequel. 

Pearce would play the role of a geneticist, and friend of Tony "Iron Man" Stark, named Aldrich Killian, reports Variety.com. The film is rumored to be partially based on the popular Warren Ellis-penned storyline"Extremis," in which Killian plays a small, but key, role.

The film, set to shoot in China, is being directed by Shane Black ("Kiss Kiss Bang Bang"). 

Pearce recently appeared opposite Kate Winslet on the HBO miniseries "Mildred Pierce," and toplined the sci-fi feature "Lockout." He'll next be seen in Ridley Scott's quasi-"Alien" prequel "Prometheus," opening in June.

"Iron Man 3" is set to open May 3, 2013.

Meanwhile, you can catch Tony Stark with his heroic buddies in next month's "The Avengers."