"Spader was my first and only choice," Whedon tells The Watcher. "He's got that hypnotic voice that can be eerily calm and compelling, but he's also very human and humorous. Ultron is not Hal [from 2001: A Space Odyssey]. Spader can play all of the levels. He's the guy to break The Avengers into pieces."
The Avengers: Age of Ultron is set for release on May 1st 2015, with Spader set to be joined in the cast by returning Avengers stars Robert Downey Jr. (Iron Man), Chris Hemsworth (Thor), Chris Evans (Scarlett Johansson), Mark Ruffalo (The Incredible Hulk), and Jeremy Renner (Hawkeye).