When actor Aaron Taylor-Johnson spoke about playing Quicksilver in The Avengers: Age of Ultron at Comic-Con 2013, many thought he had already signed on for the role, even though we had only heard he was being considered for the part back in June. Today, Marvel Studios has put out a casting call for the highly-anticipated Marvel Phase Two sequel, which confirms that he has been cast, and that Captain America: The Winter Soldier star Anthony Mackie is likely reprising his role of The Falcon as well.

However, the casting call also includes massive spoilers about the plot, that confirm what writer-director Joss Whedon revealed about the villain Ultron getting a new origin. Be warned, there will be spoilers contained below, so read on at your own risk.

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"In The Avengers: Age of Ultron Loki is gone and the new villain will be the evil robot Ultron, who has the ability to keep upgrading his own strength, making him extremely fearsome. Tony Stark/Iron Man becomes the unwitting creator of Ultron. The brother-and-sister team of Quicksilver and the Scarlet Witch become the seventh and eighth members of The Avengers. Quicksilver has extreme speed, while Scarlet Witch can cast spells and has telekinesis ability. Black Widow and Hawkeye will be key figures in the film."

In the Marvel comic books, Ultron was the creation of Hank Pym, a.k.a. Ant-Man, a character who is getting his own movie directed by Edgar Wright that will kick off Marvel Phase Three on November 1, 2015.

The casting call also revealed that production will begin in February 2014 at Shepperton Studios and in exterior locations in and around London. CLICK HERE to read the full casting notice.