As previously reported, Harris (Hedwg and the Angry Inch) is slated to portray a "chameleon salesman" in the final two episodes of the series, with Burtka to share a sexy storyline with Jessica Lange in the season finale.

The fourth season of "American Horror Story," which features the return of Lange, Kathy Bates, Paulson as well as series newcomer Patti LaBelle, premiered Oct. 8 on FX.

According to FX, "'American Horror Story: Freak Show' begins its tale in the quiet, sleepy hamlet of Jupiter, Florida. The year is 1952. A troupe of curiosities has just arrived to town, coinciding with the strange emergence of a dark entity that savagely threatens the lives of townsfolk and freaks alike. This is the story of the performers and their desperate journey of survival amidst the dying world of the American carny experience."

The season also features Frances Conroy, Evan Peters, Denis O'Hare, Gabourey Sidibe, Emma Roberts, Finn Wittrock, Michael Chiklis, John Carroll Lynch and "Hunger Games" actor Wes Bentley. 

"American Horror Story" airs Wednesdays at 10 PM on FX.