Captain America: Civil War is stacking the deck with Avengers.

'Agents Of SHIELD' Season 2: Mockingbird & Lance Hunter Set For Spinoff? Contentious Characters Teased For New Series

The 2016 film is already set to feature a host of Earth's Mightiest Heroes, and Elizabeth Olsen recently announced that Scarlet Witch will join cast as well.

Wanda Maximoff and her twin brother Peitro (Aaron Taylor-Johnson) will enter the MCU this May as the Avengers' latest foes in Age of Ultron. Known as the Scarlet Witch and Quicksilver, the sibling duo will eventually switch sides to aid the super powered collective. As tensions heat up from Iron Man (Robert Downey Jr.) and Captain America (Chris Evans), Olsen's character will have to chose sides once more.

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"I guess I'm allowed to talk about that now," Olsen teased of her involvement with Cap 3 at an Avengers 2 Meet the Filmmakers event in London, according to Nerd Reactor.

Olsen will join Downey, Evans, Scarlett Johansson (Black Widow), Jeremy Renner (Hawkeye), Sebastian Stan (Winter Soldier), Anthony Mackie (Falcon), Chadwick Boseman (Black Panther), and Frank Grilo (Crossbones) for filming at the beginning of May.

Catch Scarlet Witch in her first MCU appearance on May 1. Click the video below to see a preview for The Avengers: Age of Ultron.