Neil Patrick Harris will appear in the last two episodes of American Horror Story: Freak Show as a "chameleon salesman," while David Burtka has signed on for a role in the season finale as an unspecified character who has a "sexy storyline" involving Jessica Lange's Elsa Mars, who runs the 1950s carnival in Jupiter, Florida.
While he wouldn't offer any specific details about Neil Patrick Harris' character, Ryan Murphy said he is working with the actor to combine their specific ideas for the role.
He had very specific ideas for what he wanted to do, and I had very specific ideas, so we're working on melding those."
Neil Patrick Harris previously worked with Ryan Murphy in a guest-starring stint on the first season of Glee, which earned him an Emmy for Guest Actor in a Comedy Series.
In related news, Entertainment Weekly is reporting that Lily Rabe is returning to the series, reprising her role as Sister Mary Eunice from season 2, American Horror Story: Asylum. Sister Mary's return reportedly involves Pepper (Naomi Grossman), who ends up going from the Freak Show to the Briarcliff Asylum. Her appearance will happen in the season's 10th episode, which will serve as the show's winter cliffhanger before returning next year.