We now know another role in
Elizabeth Olsen - yes, Mary-Kate and Ashley Olsen's younger sister - confirmed to MTV she'll be playing Quicksilver's sister.
Aaron Taylor-Johnson ("Kick-Ass") was previously cast as the mutant who is the son of Magneto.
Olsen discussed teaming up again with Taylor-Johnson as a brother and sister duo after playing husband and wife in next year's "Godzilla."
"Yeah, we get to play husband and wife and then we get to play twin brother and sister," says Olsen. "It's also fun because even though in "Godzilla" we play a husband and wife, we didn't have a lot of scenes together … I'm so excited to get to work with each other more … like actually work with each other."
Olsen says she hasn't seen her costume yet for the film but that she knows about it.
In the comics, the two join the Avengers team to help take down Ultron.
Here's a photo of the brother and sister duo in "Avengers Origins: Quicksilver & The Scarlet Witch":
"The Avengers: Age Of Ultron" comes to theaters May 1, 2015.
You can watch Olsen speak about the role below: