Marvel announced today that James Spader has been cast as the villainous Ultron in The Avengers: Age of Ultron.
The studio did not specify but one can assume that he will be providing the voice for the killer robot, and not acting as the character himself. After all, he has a new TV series, The Blacklist,which is airing this fall and is currently filming. Doing voice work on the side could very well fit into his schedule. Going through hours of make-up and costuming in England probably will not.
Also not specified, but implied by the timing of the announcement, is the fact that Spader, or his voice, might be appearing in other Phase II films, most likely Captain America: The Winter Soldier, which was rumored to start the Ultron ball rolling. Although, since the announcement came so early in Phase II, there might be something in Thor: The Dark World as well.
Spader is an accomplished actor with a 35-year career under his belt. He is known for his villainous roles in films as diverse as Mannequin, Wolf, 2 Days in the Valley and Less Than Zero. Even his role in The Blacklist is that of an international criminal who helps the FBI. So he has the bad guy persona down on screen.