While Evan Peters' casting as Quicksilver in WandaVision was an early decision according to President of Marvel Studios Kevin Feige, there was some initial discussion on whether to cast his Marvel Cinematic Universe actor Aaron Taylor-Johnson in that role.According to Decider, Feige recently did a 25-minute Q&A with critics following an early preview of episodes for Marvel's next Disney+ show The Falcon and the Winter Solder. Among those questions was one on whether there was any debate about using Peters or Taylor-Johnson as Pietro, to which Feige noted, "There are discussions on everything" and explained how Marvel Studios "blue sky" all of its projects. "But I believe we ended up going with what you saw relatively early on in the development process," he finished.
Both Evan Peters and Aaron Taylor-Johnson, who coincidentally starred together in 2010's Kick-Ass, played alternate variations of Pietro Maximoff/Quicksilver in the 20th Century Fox X-Men and MCU timelines due to legal issues over Pietro and his sister Wanda being both mutants and occasional Avengers. Peters' version, named "Peter" Maximoff, debuted in 2014's critically acclaimed X-Men: Days of Future Past and later reprised his role in the new prequel X-Men timeline for X-Men: Apocalypse and Dark Phoenix.
Taylor-Johnson also appeared that year as "Pietro" in Captain America: The Winter Soldier's mid-credit scene alongside Elizabeth Olsen's Wanda, with Avengers: Age of Ultron revealing them to be Sokovian natives experimented on by Hydra before initially teaming up with Ultron (James Spader) to defeat the Avengers. Unlike his Fox counterpart, however, Pietro died in Age of Ultron after sacrificing himself to protect Hawkeye (Jeremy Renner), leaving Wanda to take revenge on Ultron and later join the Avengers.
The end of WandaVision's fifth episode, however, mysteriously revived Pietro in Wanda's Westview sitcom world using Evan Peters' form. Most recently, it was revealed at the end of the episode "Breaking the Fourth Wall" that his inclusion was the manipulations of Kathryn Hahn's Agatha Harkness, who had orchestrated a number of events behind the scenes for unknown but likely malevolent purposes. Having been absent for most of episode, Pietro reappeared to confront Monica Rambeau (Teyonah Parris) in the show's first mid-credit scene just as she was about to enter Agatha's lair.
Written by Jac Schaeffer and directed by Matt Shakman, WandaVision stars Elizabeth Olsen as Wanda Maximoff/Scarlet Witch, Paul Bettany as Vision, Randall Park as Agent Jimmy Woo, Kat Dennings as Darcy Lewis, Teyonah Parris as Monica Rambeau and Kathryn Hahn as Agnes. New episodes air Fridays on Disney+.