CAMBRIDGE, Mass. — For the boys at St. Paul’s Choir School just off Harvard Square, the weeks leading up to Christmas are always the busiest time of year. And this season, their schedules are all the more hectic, the result of a major record deal and national TV special that’s shining a holiday spotlight on the nation’s only Catholic boys choir school.

A music producer at Florida-based Aim Higher recordings, which works with Universal Music Group to distribute sacred music, heard the boys singing at a concert last year. He recorded a few minutes of it on his phone, sent it to his wife and business partner, who knew of the choir from her days as a student at Boston University, and together decided they had found their next project.

Released in October, the album “Christmas in Harvard Square” has landed the boys television specials for Boston-based Catholic TV and for PBS, which will begin airing on local stations Friday. On Christmas Eve morning, the boys will sing on Good Morning America.

“Christmas in Harvard Square” is now airing on PBS. Check local stations for information.

The album adds to an already stressful holiday season for the boys, but they say they enjoy the hustle and bustle of it all.

“I like traveling to different places in the state,” said 8th-grader Mark Flynn. “People ask us to their house to sing Christmas music. I like singing with other choirs in other churches, too.”

The album includes traditional and modern Christmas music, as well as some original arrangements from Robinson. It was recorded at St. Paul’s Church in May.

Colin Lapus, a 6th-grade student, called producing the CD a “long process,” but one that he enjoyed. “Recording in the church, too, felt different than recording in a studio, and I think that’s what the CD captures,” he said.

One day at rehearsal earlier this month, 15 of the school’s 40 boys stood in two lines, facing one another, wearing black cassocks and white surplices. They held black binders with thick with piles of sheet music, and looked up at a man standing behind a piano, waiting for instructions.

“It’s a bit throaty in a way that’s going to tire you out a little bit,” said John Robinson, the school’s music director, in his soft English voice. “Can you just bring the dynamic down a little bit, and make the most beautiful sound you’ve ever made?”

The boys apparently made some adjustments, because this time, they sang straight through for a couple of minutes.

“Brilliant,” the 31-year-old Robinson said.

Photo gallery and videos of the choir

The boys sing for about two hours each day, plus have lessons in recorder and piano, as well as a full academic regimen, including Latin and French.

The choir school model is unknown to most Americans, many of whom might raise an eyebrow at the notion of children spending so much of their days singing even as studies show American students lagging in math and science. Robinson, though, said rigorous academics and music go hand-in-hand quite well.

“We find that boys who gain confidence in the singing, particularly in focus and concentration, do much better academically,” he said.

But the priority is admittedly the music, especially in the four years since Robinson arrived from Canterbury, England, when he took the helm at St. Paul’s. The choir has been around since 1963, but Robinson is just the third music director. He was charged with revitalizing the music at St. Paul’s, connected to the parish that serves Harvard University.

“I’d been on tour to America a number of times as an organist, so I’d seen different sorts of church situations,” he said, “I had always wanted to know what it would be like to do choir training in America, because there isn’t quite the same reputation for boys choirs in America as there is in Europe.”

Raised an Anglican, Robinson wanted to convert to Catholicism, and he said there aren’t many desirable jobs for Catholic musicians in largely Protestant — and increasingly secular — England. So in 2010, he and his wife moved to Cambridge to see if they could convince Americans to embrace a rather foreign concept, and an appreciation for traditional Catholic music.

“The English choir school is very driven by repertoire,” Robinson said. “The goal is to sing all this beautiful church music that everybody knows over there.”

St. Paul’s costs just over $6,000 per year, a bit more than the average archdiocesan grade school. Most students are from Greater Boston; although there are no plans to build student housing to broaden its geographic reach, increased touring — and a higher profile — has led some families to move to Boston to enroll their sons.

To earn a spot in the school, boys are auditioned to see how well they match pitch, sometimes relying on familiar tunes such as “Happy Birthday” or the national anthem. If admitted, choristers must master sacred music, sometimes in Latin, Greek, and Italian.

“We realize in this culture the likelihood of finding boys who are already trained as liturgical musicians is not all that high,” Robinson said.

Robinson said the school is kept small to avoid what he called a “choral society mentality where they sort of drift along,” and no more than 12 boys are admitted each year. The boys are separated into different groups. The youngest are “probationers,” learning the skills they’ll need to sing with the “choristers” beginning in 6th grade. This group is the marquee choir of the school.

When their voices begin to change in the 7th and 8th grades, what Robinson calls the “no man’s land between being a treble and being a bass or tenor,” they stop singing with the choir, allowing their voices to rest.

Many students go on to attend local Catholic schools, and some continue singing in liturgical and student choirs. Some even return to join the men’s choir at St. Paul’s.

Robinson said the schedule is hectic, and students and parents have to buy into it. “The concept of a choir school is so foreign at this point that people think it’s an after-school program, or some kind of choral workshop,” he said. But he said the religious ethos of the school helps put things in perspective.

“Being a Catholic school, we see all of what we’re doing as part of our duty in worshipping God, and that sort of binds everything together into a whole that makes sense of all the moving parts,” he said.

Part of that includes service to the archdiocese, even if it means the occasional Mass on days when the boys would rather be doing something else.

“Cardinal Sean [O’Malley] loves us, he loves us, he’s great,” Robinson said. “He recently requested the boys to sing on Halloween, which didn’t go over so well with them. But we’ve given them some pizza and they’ve forgotten all about it.”

The album is bringing national attention to the school, and the choir is used to touring, with concerts in Montreal, Washington, and New York. Last year, it sang in St. Peter’s Square in Rome during one of the pope’s weekly audiences.

“Everyone is outdoors and you sort of sing as loudly as possible and you don’t really know if anyone’s hearing it. But Pope Francis was there. It was kind of amazing,” Robinson said.

But even as the holiday season means extra rehearsals for the “so many concerts, parties, Masses,” as Lapus, the 6th grader, put it, the boys say the local performances are among their favorites.

“We do big concerts in December,” Lapus said, “and Christmas Day is the best one.”

“Christmas in Harvard Square” is now airing on PBS. Check local stations for information.

Crux Catholic news service. Player build from BostonGlobe.com player.