James Spader on "The Blacklist"
James Spader on "The Blacklist"

James Spader has been cast as lead villain Ultron in Marvel's "Avengers: Age of Ultron," set to hit theaters in 2015. The sequel will be helmed by "Avengers" writer-director Joss Whedon.

Spader is a three-time Emmy winner for his role as Alan Shore on "Boston Legal" and "The Practice." He has NBC's "The Blacklist" coming this fall. He was most recently seen on the big screen in Steven Spielberg's "Lincoln."

Elizabeth Olsen and Aaron Taylor-Johnson are expected to board the "Avengers" sequel as well, as Scarlet Witch and Quicksilver, respectively.

2012's "The Avengers" made $1.5 billion worldwide at the box office, and is currently the third largest-grossing film of all time.

Whedon recently talked about the upcoming "Avengers" sequel in EW.