During an AHS panel at Entertainment Weekly's PopFest on Sunday, the creator confirmed that there's going to be a crossover between Murder House, Season 1 of his horror anthology, and Coven, Season 3.
"We do know what we're going to do," Murphy said. "It's not going to be next season, but we are going to do a season that's a crossover between Murder House and Coven together, which is very bizarre."
He clarified by saying, "There will be characters from Murder House and characters from Coven together."
The crossover won't happen next season -- Season 7 -- due to scheduling conflicts, but that's not a bad thing, because a longer lead time means a greater likelihood that AHS alumni like Connie Britton and Dylan McDermott will be able to appear. Emma Roberts, who last appeared on AHS during Coven but has stayed in the Ryan Murphy fold with Scream Queens, will also probably play a role, as she was at the panel and expressed her desire to return.
"I've [already] started going to actors from both of the seasons, quietly, saying, 'I think in this window, if you could fit us in,'" said Murphy. "So yeah, it's fun. It's weird."
Murphy previously teased that he was working on a secret project for an upcoming season of Horror Story that he described as an "experiment."
Murder House is the retroactively-titled first season from 2011, which followed the Harmon family (Britton and McDermott played the parents) as they figured out they were living in a haunted house. Coven is the third season, from 2013, and is about a coven of witches in New Orleans.
There have been some crossovers between American Horror Story seasons before, like Gabourey Sidibe's character from Coven showing up for one episode of Hotel, but this sounds like it's going to be more extensive than anything we've seen before.
American Horror Story airs Wednesdays at 10/9c on FX.