'American Horror Story' Christmas Episode: Lily Rabe Talks Ian McShane, Terrifying Scenes And More 'Asylum' Scoop

"American Horror Story: Asylum" is getting in the Christmas spirit this week. And, as to be expected, there's nothing quite like the way Briarcliff celebrates the holiday season.

In the episode, "Unholy Night" (Wed., Dec. 5, 10 p.m. EST on FX), highly-anticipated guest star Ian McShane plays a very twisted Santa Claus and Sister Mary Eunice (Lily Rabe) has St. Nick in her custody now that she's in charge at the asylum.

Rabe started the season as the innocent, perpetually nervous nun who was scared to eat a candy apple and has become the diabolical, deranged, yet wickedly funny woman who is anything but pious ever since the devil possessed her.

The actress, who also appeared on "American Horror Story's" first installment, took the time to talk to HuffPost TV via phone about working with McShane, her upcoming romantic scene with an unlikely character, what a Christmas tree looks like at the asylum, bringing a sense of humor to Briarcliff, being terrified to sing "You Don't Own Me" and what she begged "American Horror Story" co-creator Ryan Murphy to include this season.

You are absolutely terrifying this season.
[Laughs.] Thank you!

Last week's episode had a lot of great Sister Mary Eunice moments, especially in the scene with the Angel of Death. What was it like working with Frances Conroy again?
She's so amazing. I've been such a fan of hers. I was such a fan of hers on "Six Feet Under" and last season [on "American Horror Story"], I thought she was so amazing. I had a really wonderful time with her. I think also the dynamic between those two characters -- meeting these opposite and equal forces in terms of good and evil, or whatever it is in that moment -- was really so much fun to play. We had such a good time with it.

Ryan Murphy said that the Angel of Death will return. Can you tell us anything about her upcoming interactions with Mary Eunice?
I can't.

Ryan will kill you.
[Laughs.] I can never tell you anything but what Ryan tells you. [Laughs.] That's the rule. But yes, she's definitely back and we have more to do together for sure.

Last week, it was amazing when Mary Eunice's voice came out a bit and then the devil pulled her back. Was that difficult to do?
Sure, I guess. I mean, yes, playing the part can definitely be very painful, but I also think that that struggle -- even though it's materialized in that moment maybe more than other moments -- it's always going on. Playing that scene was very painful, but you're also just playing the scene and doing your best to tell the truth of the moment and, more importantly, of her struggle. Although her old voice doesn't really come out very often -- because I think everything that has taken her over is so much more powerful than she is -- that struggle is alive in every second.

Is it difficult to leave the character behind when you're done shooting each day?
Yeah. I find it difficult. I mean, luckily, we usually wrap shooting for the day so late that there's nothing I have to go on to do in terms of seeing friends or trying to be a normal person. [Laughs.] I'm usually just trying to go to bed and trying to read my book and fall asleep eventually. But yes, it takes a while at the end of the day to set aside whatever you've been going through [on the show]. But I don't see that as a negative thing really. I think part of what that is is that we all have these great parts. So I wouldn't trade it to be skipping home and running off to drinks at the Chateau [Marmont] or something. I'd rather be going home and staring at a wall for a little while and going to bed. [Laughs.] I really do love my job.

At least Sister Mary Eunice brings some comic relief.
Oh, I'm so happy to hear you say that!

Was she always intended to provide that humor?
I didn't know much, but I knew I'd be playing Sister Mary Eunice, which instantly made me laugh. Just the name I think is so hilarious. I remember in early conversations with Ryan, he said, "She's going to be this and this and oh, she's going to be really funny!" I'm so glad that the writers give me a joke here and there. It makes me really happy to try to be a little funny. Of course, you're never playing for the funny really, but people have told me that they're relieved to be able to laugh sometimes with her or at her, frankly. That's just a thank you to the writers for giving me that stuff. From the beginning, there was some potentially funny stuff, but you have no idea if it's going to be funny [when it airs]. It's not like doing a play where you can hear people laugh. So, of course, that could've all fallen flat, but I'm so glad it didn't and I really just have to say I think it's because the writers gave her this opportunity for some laughter. That dark comedy, that black comedy is what makes me laugh, so sometimes just reading the script, I'm laughing out loud. But I never know if that's going to happen when I'm saying that line. I'm worried that those laughs might totally go away.

The scene last week where she was singing "You Don't Own Me" to the crucifix and then impersonating Sister Jude on the phone was hilarious. Did you have fun filming that?
Oh, good! I did! I had no idea if it would be funny. I was actually really terrified shooting that scene because it was one of those scenes that just said in the script: Mary Eunice, in her red slip, sings, "You Don't Own Me." That was what we had. So I really have to give thanks to the director and the crew for just sort of letting me go. I said, "As much as we can, can we just shoot the room, ending up with her screaming at the crucifix?" Some of the things that happened I think were a little too extreme and didn't make it into the final cut. [Laughs.] But it was really fun and really exhilarating and super terrifying.

The other thing was I was singing with an earbud so luckily, as it played in the final cut, I was singing along with Lesley Gore. But I had never done that with an earbud where you're just running around, screaming and no one else is hearing the music but you. [Laugh.] But one of my great secret dreams is to be in a musical -- or better yet, a movie musical -- so if that's as close as I get, that was pretty fun.

It brought me back to the final scene of the movie "First Wives' Club." Have you seen that?
Oh, right! Yes!

Now that Sister Jude has realized that Mary Eunice is possessed, will she confront her in this week's episode?
I can't tell you! [Laughs.] I think that anything that's a spoiler is just the worst thing on this show because the people I know who love to watch it are always like, "Tell me! No, don't tell me! Tell me! Please, don't tell me" ... even though I wasn't going to tell them anyway. To me, part of the joy of watching this show is not knowing anything.

In the Christmas episode, Mary Eunice comes into contact with Santa Claus, who's played by Ian McShane. What was it like working with him?
That was such a highlight. It was so fantastic. I'm such a fan of his. I loved "Deadwood" so much. And we got along really well and we have ... [laughs] very wicked and really delicious stuff to do together. We had a lot of fun. I hope we get to work together again. He's such an incredible actor. And also, it turns out we'd met a couple of times, but we never spent any real time together. He's a great guy and a lot of fun.

Ryan said a bit of thought went into how the Devil would decorate a Christmas tree.
Oh, yes! [Laughs.] It's exactly appropriate. It's just how Mary Eunice at that time would decorate the tree I think. It's pretty funny.

I'm disturbed. I don't know if I want to see that.
[Laughs.] I mean, I certainly know what he's referring to, but I can't really say anything else.

Is it in this week's episode?
No, it's not.

I spoke with Zachary Quinto earlier in the season and he said he was bummed you two didn't have more scenes together.
Oh, I feel the exact same way. We used to always sort of look over at Ryan and say, "Hey! What about if Thredson and Mary Eunice ..." He was like, "No, no, no. I don't think so. Love you guys!" [Laughs.] There are those certain characters that don't intersect really. But it's not that we have nothing to do together. He's a very dear friend and I think he's such an incredible actor and we also have just a lot of fun together so it would have been fun, but I also have a really great time with everyone.

And that's what's so unique about the style of "American Horror Story." You could work with the same group of people for multiple seasons, but who you interact with will change because the story changes.
Yeah. I mean, I also don't have a lot with Evan [Peters] who I think is amazing, but yeah, that's the nature of the show.

What's been your favorite scene so far this season?
I had a really, really wonderful time shooting that scene with the little girl [in "The Origins of Monstrosity"]. I was so amazed by her. She was so beyond her years. She was one of those kids who you spend the day with and half-way through the day you realize you've completely forgotten that she's a child because she was so sophisticated and funny and thoughtful. Also, I loved that scene. I thought it was so dark and that was a lot of fun to play.

You know, I loved shooting the pilot. I loved shooting the pre-possession. There was also a scene I shot with Jessica [Lange] that I don't think has aired yet that was also unusually special. There are a lot. It's a great place to go to work and I had such a great time playing the part even when it was very painful.

Will you be back for Season 3 of "American Horror Story"?
I can't answer that.

Would you want to come back for Season 3?
Oh absolutely, yeah! I'm just having the greatest time. I think for an actor it's just the most ideal situation to get to do this repertory thing on television. It's a real gift. And to have Ryan running the show is also a gift because he keeps it so alive and so brave. It's just a lot of fun.

"American Horror Story: Asylum" airs on Wednesdays at 10 p.m. EST on FX.

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