Murphy did not say what character Gerber will play on the series.
He announced last week that Season 10 of his FX anthology series will be called Double Feature.
The words: "Two horrifying stories... one season. One by the sea... one by the sand," scrolled across an ocean beach in a video Murphy posted on social media.
The post also gave the supernatural-themed project's location as Provincetown, Mass.
The writer-producer previously announced this season's cast will include Macaulay Culkin and Leslie Grossman.
Season 9 of AHS, subtitled 1984, aired in 2019.