So long, Loki.

Casting is currently underway for the upcoming sequel to "Avengers," "Avengers: Age of Ultron" -- and now, we know who will be playing the film's new villain.

"James Spader will face off against Earth’s Mightiest Heroes as the villain in Marvel’s 'Avengers: Age of Ultron,'" a press release from Marvel just announced.

"The Emmy Award-winning actor will play Ultron in the Avengers’ much anticipated return to the big screen from writer/director Joss Whedon," the company continues.

Spader is famous for his work as Alan Shore on "The Practice" and "Boston Legal," and is already generating big buzz for CBS' upcoming show "The Blacklist." He's also starred in movies like "Lincoln," "Stargate," "Sex, lies and videotape" and "Pretty In Pink."

Since the character is a robot, it's safe to say we won't actually be seeing much of Spader in the film.

Director Joss Whedon recently talked to EW about the big bad bot, saying "He’s always trying to destroy the Avengers, goddamn it, he’s got a bee in his bonnet. He’s not a happy guy, which means he’s an interesting guy. He’s got pain." 

"As a character I love [Ultron]," Whedon says, "because he’s so pissed off."

As for Tom Hiddleston, who played Loki in the first flick, he's already sent James a congratulatory message on Twitter:

For more info on Marvel's upcoming movies, including "Captain America: The Winter Soldier," "Thor: The Dark World" and "Guardians of the Galaxy" check out 10 Things We Learned at D23.

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