It’s a pretty reasonable assumption that a majority of New Yorkers have seen at least a commercial for the 1964 animated holiday staple, “Rudolph, the Red-Nosed Reindeer.” Now people can see that stop-motion movie come to life on the stage at The Theater at MSG.

San Diego actress Sarah Errington is taking on the title role, glowing red nose and all, which she calls a “magical” experience.

“It’s pretty cool walking into the rehearsal room and they have the trees that look like the little trees that were in the movie and the puppets that look like the little misfit toys,” she says. “It brings you right back to childhood, that nostalgia. It’s time for the holidays.”

amNewYork spoke with Errington about the show, which opens Dec. 1, during the early days of rehearsals last month.

What was your relationship with the animated special?

I definitely grew up watching the original 1964 version. It was a staple with my family. I think pretty much it would start playing after we had Thanksgiving dinner. It’s a favorite. It’s been pretty surreal being a part of this process because everything about the production is just like the movie. It’s pretty magical.

How does one get into the mindset of a reindeer?

You know, it’s kind of funny. I’m anxious to put on the costume to see how that affects things. I’m definitely getting the reindeer stance, remembering there’s antlers on top of your head and all that good stuff. It’s just keeping that childish energy, I would say, that the character of Rudolph has. That innocence.

What can you tell me about the costume?

I’ve worn lots of different costumes before. This is my first time playing a reindeer. There’s a first time for everything. We aren’t on all four legs, which is awesome. We are upright. The costume is kind of a one-piece suit, it looks just like the movie, and then there’s a headpiece — I have the Rudolph head on top of my head, which should be interesting. And the nose does glow red, which I can’t wait to see. I think it’ll be interesting wearing the costume. And then I will be flying, so that’s a whole other exciting element to throw into that as well.

Have you performed in New York before?

This is actually my New York debut, it’s my first time working here. I’m originally from Northern California and now I’m based out of San Diego. It’s been quite an honor and journey to earn the role of Rudolph, and to be a part of this company. It’s been an adventure for sure. I’ve been to the city before for vacation and auditions. This is my first time working, I couldn’t ask for a better experience. And to be able to be at the Theater at Madison Square Garden is pretty fantastic. I can’t complain.

You live in San Diego — are you ready for being in New York in the winter?

I am. I packed lots of sweaters, long underwear. I’m very coldblooded, so we’ll see how I survive. It’s going to be exciting for sure.

The song “Rudolph the Red-Nosed Reindeer” is an earworm, for sure. How do you handle having to be so immersed in that song without going crazy from hearing it over and over and over again?

To be perfectly honest, we’ve only been here a week so it hasn’t gotten too old, yet. ... Kids and the way they react, if they see something they love, you hear it. They have no filter yet, which is wonderful and beautiful. I don’t think you do get sick of [the song] because you’re back with that childlike innocence and that element of magic. When we perform this song in the show, I’m actually flying, so I don’t know how much more holiday spirit and magic and glitter and all that sorts of stuff. I think it’s going to be pretty overwhelming in the best way. But we’ll see how I feel three weeks from now. But I don’t know if I will get tired of it because it’s the perfect amount of time, just over the holidays.