According to EW, the Modern Family star will appear in a November episode of the forthcoming FX series.
Stonestreet will play a new patient of lead character Dr. Ben Harmon, played by Dylan McDermott, who seeks help to cure his fear of urban legends.
The actor was recently cast in a new HBO biopic about the life of silent movie star Roscoe 'Fatty' Arbuckle.
Stonestreet is up for a Primetime Emmy Award in the 'Outstanding Supporting Actor in a Comedy Series' category for his performance on Modern Family.
American Horror Story will premiere on FX on October 5.