Guilford High School (GHS) Voices, the school music program’s select group of choral singers, has had a very busy holiday season. The front-and-center spot at the school’s annual holiday concert at First Congregational Church in front of sold-out crowds and rousing applause might have been a fitting climax for GHS’s talented songsters, but this year, there was something bigger coming.

On Dec. 10, the day after the holiday concert, GHS Voices opened for multi-platinum selling and world-famous a capella group Pentatonix at the Mohegan Sun arena, in front of thousands of spectators in a last-minute, once-in-a-lifetime experience that GHS Choral Director Rachael Allen said is something she’s sure her 33 young singers will never forget.

“That’s one for the books,” said Allen. “You should have seen their faces when I printed out the picture of us on the stage, and put it on the wall the other day,” she said. “They were so excited to see it up there—just the way they felt about having that experience together was the valuable part.”

The incredible opportunity to be on a stage of that size and to interact with such a high-profile musical act came without much fanfare, or time to prepare, Allen said. Though she said she wasn’t at liberty to discuss all the specifics, Allen said there was a “connection” between GHS and Pentatonix that resulted in the school sending in an audition tape.

After not hearing anything back for some time, Allen said she got the call that the Voices would be singing at the show less than two weeks before the scheduled performance.

One slightly disappointing thing, Allen said, was that she wasn’t able to break the good news to the students in person.

“Because I got the news the day before Thanksgiving, they were already gone—everybody was gone” on break, Allen said. “Because I had to get things rolling, I had to tell them in an email. So I didn’t get to experience their reactions.”

Allen said that the short notice never caused her or the kids any stress, as all the practice they had from caroling, concerts, and other events meant the group was extremely well-rehearsed. Standing in a 10,000 seat arena, however, in the same venue that has hosted Taylor Swift, Jay Z, and Kenny Chesney was an entirely new experience—though in some ways, not all that different from what they do all the time.

“It was a little surreal walking through [the backstage] with 33 high school kids dressed in tuxedos and gowns,” Allen said, laughing.

Voices also had a unique chance to carol in the lobby and outside the arena as a sort of warm-up for the concert, interacting directly with audience members, Allen said. After that, the GHS singers took the stage themselves, in the shadow of the jumbotron screen and with around 7,000 people focused on them.

“It was funny—I was talking to one of the kids...and both of us had the same reaction to how it felt,” Allen said. “It felt, at the same time, surreal and strangely normal, which is a really weird thing to say, I know. But once we got up there, we just did our thing. It wasn’t any different from any other performance, as far as what we needed to do.”

“[The kids] come off as just sort of seasoned pros, because they do so much performing.”

Allen said a number of students told her they were actually more nervous before the holiday concert.

“Because [at the holiday concert], number one, you can see everyone. And number two, it’s people they know,” said Allen.

For a high school choral program—even one of the premier programs in the state—participating in a big-time concert had way more to do with giving the kids a chance to show off their talents and create cherished memories than it did with building reputation of prestige for GHS, Allen said.

“The thing that I think the most about is what it meant to the kids,” Allen said. “That special experience that they’re never going to forget.”