TVGuide.com said few details about his character or story arc have been disclosed.
Murphy said on Twitter, however, McShane will lock horns with Jessica Lange's character Sister Jude, one of the nuns in charge of the insane asylum at fictional Briarcliff Manor in 1964, TVGuide.com said.
McShane's small-secreen credits include "Deadwood," "Kings" and "Dallas."
Season 2 of the "American Horror Story" anthology is to debut Oct. 17 on FX.
Notable deaths of 2014 [PHOTOS]