Hahn will reprise her role as Agatha in the new series and WandaVision head writer Jac Schaeffer will return as writer and executive producer. The currently untitled show has been described as a dark comedy, but any other plot details are still being kept under wraps in typical Marvel fashion.
When we first meet Hahn's character in WandaVision, she's simply Wanda and Vision's nosy next-door neighbor who's keen to befriend Wanda. However, it turns out she was Agatha All Along – that is, a powerful witch who we later find out survived the Salem Witch Trials hundreds of years earlier. She proves to be a worthy opponent for Wanda (AKA Scarlet Witch), but not quite worthy enough – in the season finale, Wanda uses her powers to trap Agatha in the town of Westview in her Agnes persona.
It's unclear whether the series will explore what happens in Westview after Wanda leaves at the end of WandaVision or whether it'll delve into Agatha's past instead – there's plenty of material there in the three hundred or so years between the witch trials and the present day.
If any WandaVision character was going to get their own spin-off, it's no surprise that it's Agatha – she quickly became a fan favorite and Hahn received an Emmy nomination for her performance.
While we wait for the new Marvel series to arrive on the streamer, check out our list of the best shows on Disney Plus that you can watch right now.