The Marvel Cinematic Universe is expanding to include an actor from one of Netflix's biggest young adult franchises.

Joe Locke will join 'Agatha: Coven of Chaos', the greenlit spin-off from Marvel's runaway success 'WandaVision'.

The Disney+ series sees Kathryn Hahn reprise her fan-favourite role of Agatha Harkness (of "It was Agatha all along" fame) for her own standalone production which will delve deeper into the madness of the MCU supervillain. It's not yet known whether this will be a prequel or a sequel series.

Locke, who plays Charlie Spring in Netflix's 'Heartstopper', is only the third actor to join the cast of the mysterious production but it's believed he will play the lead male role in the series. Emma Caulfield Ford, who played prim and proper neighbour Dottie in 'WandaVision', will also be returning.

There's been a lot of positive buzz surrounding the casting of Joe Locke in 'Agatha: Coven of Chaos', plus a lot of speculation as to who he could be playing. Alice Oseman, who created 'Heartstopper', tweeted their support for Joe's next big TV adventure.

As for who Locke could be playing - speculation is rife that he's been cast as Wiccan, one of Wanda/Scarlet Witch's twin sons. So far, Billy Maximoff has only appeared as a child in 'WandaVision' and 'Doctor Strange in the Multiverse of Madness', played by Julian Hilliard. In Marvel Comics, Wiccan has magical powers inherited from his mother and is also a prominent gay character. If the rumours are true, expect Tommy/Speed to join the cast by an actor around the same age as 19-year-old Locke.

It's been quite a busy week for the 'Heartstopper' gang, as earlier this week Locke's co-star Kit Connor announced online that he was bisexual. Connor posted on Twitter that he was "forced" to come out due to speculation and comments by fans of the Netflix show and its original source material. 'Heartstopper' has two more seasons on the way at Netflix.

Another 'WandaVision' spin-off is believed to be in the works at Marvel Studios, which will focus on Paul Bettany's Vision and what happened to him after the season finished. This, however, has not yet been confirmed by Marvel.

'Agatha: Coven of Chaos' is expected to debut on Disney+ in late 2023.