BOSTON -- The Sistine Chapel Choir, often referred to as "the Pope's Choir," will sing in Boston this summer as part of its first-ever U.S. tour.

Based out of Rome and serving as the pope's personal choir, the Sistine Chapel Choir is comprised of 20 professional singers, chosen from around the world. Its treble section, called the Pueri Cantores, is made up of 35 boys between 9 and 13. As part of their training, the Pueri Cantores attend an exclusive school, the Schola Pueroroum, which provides musical education as well as a typical school curriculum.

The choir is one of the oldest in the world, having been formally established in 1471 with roots that go back to the early Middle Ages, and plays an active part in papal celebration in St. Peter's Basilica and in the Sistine Chapel.

Its music has relatively been confined to Rome during much of its existence, as recordings have historically been prohibited within the chapel itself. In recent years, however, the choir has been made more available, appearing on a live album in 2014 and an album in 2015 recorded inside the chapel.

The 2018 U.S. Tour will be the first time the choir will be performing in America, and follows a performance last year in Canada. The tour will make several stops at locations around the country.

A single concert will be held in Boston on July 17 at the Boch Center, located on Tremont Street. Beginning at 7 p.m., the concert will also feature two opening choirs: The Cathedral of St. Joseph Parish Choir and The Saint Anselm College Choir.

In a telephone interview April 5 with The Pilot, Sistine Chapel Choir singer Stefano Guadagnini said performance will consist of pieces from the Renaissance, including works from Giovanni Pierluigi da Palestrina, Cristobal de Morales, and Gregorio Allegri.

Allegri's "Miserere mei, Deus," one of the most famous pieces from the Renaissance, will be sung, said Guadagnini. It is one of his favorite pieces to sing, he said, adding that he will be featured as a soloist.

Having been in the choir for about a year, Guadagnini considers himself a new member of the choir. Born and raised in Rome, he was a professional singer prior to his involvement with the choir, he said, and performed private concerts.

Unbeknownst to him, the director of the Sistine Chapel Choir, Maestro Msgr. Massimo Palombella, was present at one of these concerts, and later called Guadagnini to offer him a spot.

"It's something that never happens, said Guadagnini, "so when it does, you have to go for it."

Choir members practice for at least three hours a day, Guadagnini. He sings among the altos, which he said is a "natural place with my vocal register."

"I feel fortunate and lucky to be part of (the choir)," he said.

Having never been to Boston, Guadagnini said he is looking forward to experiencing the city and seeing new things.

"It will be amazing," he said.