New updates to the cast of "American Horror Story: Freak Show" will have some familiar, and not-so-familiar, faces appearing on the FX series.

Sources have confirmed that Lily Rabe from Season 2's "Asylum" will reprise her role as Sister Mary Eunice, and Neil Patrick Harris and his husband David Burtka will also make guest appearances.

While the thriller series typically has reoccurring actors play new roles every season, Rabe's Sister Eunice will return, reportedly in Episode 10 of the current season. 

This is the second time an actor in Ryan Murphy's hit series appears across seasons as the same character. Naomi Grossman returned this season as her character Pepper, also from "Asylum." Rabe's character crossover will play into that storyline and how she got to Briarcliff Manor, where the second season was set.

Meanwhile, Harris and Burtka won't appear until the final two episodes of the season, according to E! News. Harris is currently busy preparing to host the Oscars and playing host on a new variety show on NBC. His character will reportedly be a salesman.

"I wrote a letter to Ryan [Murphy] asking if I can be in it, even though I wasn't even available to be in it ... I just love those series, and 'Coven' was fantastic ... to do one that involves any kind of freak, circus nonsense is going to be so unsettling to watch," Harris told E! in July. "Can't wait!"

Burtka will appear in the finale to mess with Jessica Lange's Elsa Mars.

Murphy, the co-creator of the show, said spoke with Harris in October about his role in the show.

"He's game. He had very specific ideas of what he wanted to do, and I had very specific ideas, so we're melding them," Murphy said. "He's awesome, one of our great entertainers."

Patti LaBelle, Matt Bomer, Wes Bentley and Celia Weston will also guest star in this season's episodes.

"American Horror Story: Freak Show" airs Wednesdays at 10/9c p.m. on FX.