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The news came after both Samuel L. Jackson and Olsen discussed the casting in recent interviews, though obviously Marvel needed to put out the word itself. Marvel's announcement noted that both Olsen and Taylor-Johnson have experience working on critically-acclaimed films, and that audiences could first see the pair at work in the upcoming "Godzilla" remake, which hits theaters in May 2014.
Earlier this month, Olsen said joining the Marvel universe was "so fun," and the actress gushed over both Taylor-Johnson and "Avengers" director Joss Whedon.
"I just love him," the actress said of Taylor-Johnson, adding she was "so excited" to work with him again. "I think it's going to be fun," she said.
Scarlet Witch and Quicksilver are fraternal twins (and the children of "X-Men"'s Magneto, though don't expect that rival Fox property to get any mention in "Avengers"). Scarlet Witch can cast hexes and control probability, while Quicksilver can run at superhuman speeds.
"Avengers: Age of Ultron" hits theaters May 1, 2015.