BOSTON -- Noah Guidel-Mendez was nervous to sing the "Anima Christi" and Faure's setting of the "Pie Jesu" before an audience of senior priests at Regina Cleri.

There was only one way to get through his stage fright.

"I basically just sang," the 11-year-old said.

Noah is a parishioner at St. Mary's in Waltham. He and 57 children in the parish summer program performed for senior priests on Aug. 21, singing classical prayers like "Dona Nobis Pacem" and contemporary hymns like "Above All," as well as secular pop songs and patriotic tunes in celebration of the U.S.'s 250th anniversary.

Regina Cleri Executive Director Stephen Gust said that he and the senior priests were "genuinely moved by the beautiful concert."

"We can't wait to welcome everyone back next year and to continue building these joyful connections with young people who bring such light and energy to our community," he said.

"To see them working hard and preparing and to see them perform so well, it just reflected the joy they had about being around the Church," said Father Michael Nolan, pastor of St. Mary's.

The children spent two weeks rehearsing for the concert, praying together, creating art projects, and training to serve at Mass during the summer program. Many of them sing in St. Mary's choirs but had never sung all together before. They represent the diversity of their parish, hailing from its English-speaking, Hispanic, and Ugandan communities.

"Singing religious songs is a really great thing to show my faith," Noah said.

Hans Katende and Catelyne Nalukenge, both 14, sang the "Stabat Mater" as soloists.

"I like to do this because it's good for me, since I know that I'm singing for God and other people," Catelyne said.

By singing hymns, Hans is able to share his faith.

"Personally, I think they're very calming and also a very good and beautiful way of representing your faith," he said.

He was proud to receive compliments from the senior priests after the concert.

"It was good to know that they've done a lot for our faith," Catelyne said.

Sebastian Guidel-Mendez, Noah's older brother, sang "My Way" as a soloist. Singing in the choir is a way for him to combine his love of singing and his love of his Catholic faith.

"It felt nice," he said.

At first, the 14-year-old was a bit embarrassed to sing with his younger brother.

"I soon grew to learn to appreciate his voice, as well as be proud of it, since I can sing with my brother, and we can sound good while doing it," he said.

Which brother is the better singer?

"I'd say we're equal," Sebastian said. "Noah is at a really good point where he's at right now, and I can't wait to see how much he grows."

Noah agreed.