There’s already a slew of characters in play on American Horror Story: Freak Show, but when folks like Neil Patrick Harris, David Burtka and Lily Rabe want in, you give them roles.  Harris will guest-star on the 11th and 12th episodes while Burtka is set to make his appearance in the 13th, the season finale.  As for Rabe, she’s going to be in episode 10.  That’s the final episode before the holidays, so there’s a chance her character could be involved in whatever outrageous winter cliffhanger the writers come up with.

Hit the jump for more on their roles.  American Horror Story: Freak Show airs on FX on Wednesday nights at 10pm.

The Harris/Burtka casting news comes from TV Line.  They’re reporting that Harris will play “a chameleon salesman” while Burtka will step in for “a sexy storyline with Jessica Lange’s batty chanteuse.”  Here’s what Ryan Murphy had to say about Harris’ appearance:

“He had very specific ideas for what he wanted to do, and I had very specific ideas, so we’re working on melding those.”

There's no mention of an NPH musical number, but it's hard to imagine Murphy and co. passing on the opportunity to have him do a duet with Lange's character.  Or perhaps something with Bette and Dot.  Or, wouldn't NPH be the perfect guy to lead Elsa's Cabinet of Curiosities in a full company song?  Then again, I've got no clue what any of that would have to do with him being "a chameleon salesman."

Lastly, remember when Naomi Grossman was named the first American Horror Story cast member to play the same role in two seasons?  She’s not alone anymore.  According to EW, when Rabe makes her episode 10 appearance, she’ll be portraying Sister Mary Eunice, her character from American Horror Story: Asylum.  As one might expect, Sister Mary’s arrival is tied to Pepper and will reveal how she makes her way from the freak show to Briarcliff.  Sister Mary didn’t become demonic Sister Mary until episode 2 of Asylum, so the character we’ll get in Freak Show will likely be meek, naïve and harmless.