According to Deadline, Joe Locke's role in "Agatha: Coven of Chaos" is described as "a gay teen with a dark sense of humor," which immediately led fans to believe he'll be playing Wiccan.
Marvel fans discussed the casting on Reddit and have come to the conclusion that everything points to Locke playing Wiccan. Not only does the character description resemble Wiccan's comic book personality, but Locke looks just about as similar to the teenage warlock. u/cbekel3618 said, "WICCAN. If he is playing Billy, then this is definitely a good pick! He's a pretty solid actor in 'Heartstopper,' definitely looks the part, and it'd be dope if they cast an openly queer actor for the role." u/KostisPat257 had a similarly strong response to the news, saying, "Couldn't get a more perfect Billy [Wiccan] holy s***."
Other users instead focused on a potential "Heartstopper" reunion in the MCU. Locke and his costar Kit Connor have been a popular fan cast for Wiccan and Hulkling, a fan-favorite gay couple from Marvel comics, and Locke's casting brings that one step closer to reality. u/Medium-Midnight mentioned the coincidental casting saying, "Sometimes I wonder if Marvel pays attention to fan casting because a lot of people wanted him as Wiccan and Kit Connor as Hulkling."
For those unfamiliar with the comics, Wiccan, also known as Billy Kaplan, is the reincarnated version of one of Wanda Maximoff's sons, William Maximoff. MCU fans will recognize William Maximoff from "WandaVision" and "Doctor Strange in the Multiverse of Madness," played by Julian Hilliard. If the MCU decides to go the reincarnation route with the character, Joe Locke would be an incredible choice for an older Wiccan.
