Gabourey Sidibe joins "American Horror Story: Coven" cast Gabourey Sidibe is joining a new "Coven." The Oscar-nominated actress has another gig lined up following the end of production on her current series, Showtime's "The Big C." Sidibe is set to star on the upcoming third season of "American Horror Story." Oscar-winner Kathy Bates is also expected to join the cast for season 3. Series creator Ryan Murphy was the first to break the news about Sidibe on Monday: Gabourey Sidibe The premise and characters of "American Horror Story" change each season. The first season took place in a haunted house, while the second season was set at an insane asylum. This upcoming season, "American Horror Story: Coven," will center around witchcraft. Details on Sidibe's character have yet to be revealed. Sidibe's current series is now wrapping up after three seasons with a four-episode special titled "The Big C: Hereafter," which kicked off Monday on Showtime.