The name Margo Seibert doesn't ring a bell to most theatergoers; now, at least. In six months, however, she is poised to become the toast of Broadway. In February, Seibert will make her Broadway and major New York City debut in Rocky, Lynn Ahrens and Stephen Flaherty's highly anticipated musical adaptation of the iconic Sylvester Stallone film, at the Winter Garden Theatre.

But first up for this graduate of American University (with a degree in International Relations, naturally) is the musical in which she currently stars, Prospect Theater Company's Tamar of the River, running through October 19 at Baruch Performing Arts Center. Seibert, whose voice can flawlessly run the scales and not miss a single note, takes on the title role, a young woman from a war-torn world who is called forth to create peace.

TheaterMania chatted with Seibert about her experiences and precisely why the next few months will be the most exciting moments in this young performer's life.

Margo Seibert
Margo Seibert
(© Matthew Murphy)

Were you familiar with the biblical story behind Tamar of the River before coming aboard this production?
Only barely. As much as I read it, I realized it wasn't actually that helpful. We use the same names and a suggestion to the time period, but [that's it]. It used to end in a similar way [as the bible story] — she found out she was pregnant with Judah's child. That doesn't happen anymore. When you work on a new musical and you have so many changes that happen, you also find yourself ending up really exploring it when you're running the show in front of audiences. Which is fun. And nerve-racking. And super fun. [laughs]

You've been with the production for quite some time.
I've been really fortunate to workshop it for a few years…The show has changed...I feel pretty good about it now that the changes have stopped. We cut out a seven-minute sequence, a double song-scene thing. I think it's hugely helpful. Luckily, [director] Danny [Goldstein] was like "let's try this cut" and it worked really well.

His staging is so unique, with you and your fellow actors performing the show on a runway in between seating areas. Can you see the audience? Does that affect you as a performer?
Sometimes I can. I have a few moments, especially when I speechify to them, when I turn around and see a face I recognize. For the most part I don't. I'm always trying to stay conscious of whether or not I'm really blocking off one side from seeing what's going on. You forget sometimes. When I was younger, I worked in the round for a long time, which was great training. But every once in a while, I'm like "I'll just scoop my body over here and hope the left side doesn't miss anything." I've never worked on a runway style stage, but it's so much fun. [Goldstein] has a really awesome eye for the potential.

You're onstage for most of the piece, and the score seems incredibly taxing to sing, at one point requiring you to do vocal runs of the scales. How long did it take you to learn?
It's taken a while. Three years ago, when we were given the opportunity to do the workshop at Signature [in Washington, DC], I started working with [Tamar composer] Marisa Michelson, meeting with her in her apartment. She has a very specific way of working. It was discouraging because I was intimidated. Now, three years later, she's my voice teacher. Being able to work on a piece of music for that long totally serves the piece. I don't have to think about hitting the notes of those runs. Tamar is saying she's crying; it's the feeling of somebody crying but it's expressed in this very musical way. It's very fun to sing. When I'm working on new pieces and working with new composers, if a piece really gets to me, it's because the singing and speaking merge so flawlessly that you are okay with it being expressed in song.

Is that something that drew you to Rocky?
When you hear something like that, when you hear you're gonna go in and audition for this musical, I don't know how you can not be skeptical. Then I received the material and I was like, "This is beautiful." The music is gorgeous, and all I have heard from people is how much they enjoyed it and how simple it was. The script is so good. The craziest thing is that I had no connection to the piece whatsoever. I didn't know it was going on, I didn't know anybody on the team. My agents called me and I went in and they saw me eight times. I was like "Okay, I must be doing something right that they need to see me again."

What about Rocky is going to surprise audiences the most?
What I hope people are super surprised by is the heart of it. There's a reason that Stallone had such an amazing career based on the writing of this movie. People identify as these characters. I'm hoping that comes across in the musical. It's incredibly important in this telling of the story…maybe I'm saying that because I'm involved with this part of [it].

What are you looking forward to most?
I'm looking forward to being privy to this kind of experience at this level, and what that means. Getting the opportunity to work with Alex [Timbers] and Lynn [Ahrens] and Stephen [Flaherty]. How we create a new musical, even though it's a piece that people know. I've had the opportunity to work really closely with writers before, especially in the NYU Graduate in Musical Theater program. I don't know what that means for Rocky, but so far, even in the audition room, Alex is really letting me make my own choices and take chances. I'm really looking forward to that in the rehearsal process. And how many changes we have. How the audience responds. To play such an iconic character. I hope I do her justice.