The 35-year-old actor has joined the fourth run of the hit FX show, which has the full title 'American Horror Story: Freak Show', reported Variety.
Bentley will appear in the show's two-part Halloween episode.
'The Hunger Games' and 'American Beauty' actor will play Eddie, a "dark tormentor" who is "hell-bent on revenge".
Earlier this year, further details about the upcoming carnival-themed season were confirmed.
It will be set in Jupiter, Florida and star Jessica Lange as a German woman managing one of the last US "freak show" attractions.
It will be Lange's last appearance on the series.
