The Robert F. Kennedy Elementary School Choir, of which I was a member, had just finished a rousing version of “Jingle Bells” when my heart started pounding. The moment I was dreading had finally arrived.

 We were a bunch of Providence kids in our school’s gymnasium, where I had performed many times before, but as a point guard on Kennedy’s youth basketball team, not as a soloist at the annual Christmas concert.

 It wasn’t supposed to be this way. I was originally paired with another fifth-grader to sing a duet of “Go Tell It on the Mountain,” the popular spiritual celebrating the birth of Jesus. But on the day of the concert, my fellow caroler was home with the flu.

 My mind raced upon hearing the news in the schoolyard, and not to good places. I had to sing alone? What if I forgot the words to the verse my friend, the better singer, was to have sung? Or worse, what if I opened my mouth and nothing came out?

 I had been selected for the choir two years earlier after being summoned, along with my third-grade classmates, to the music room in the school basement. Each of us sang a line or two from “Oh Susanna” as the choir director accompanied us on the piano. With her cat-eye glasses, muted floral dresses, and white pearls, she reminded me of my Italian grandmother. Apparently, my voice was OK; I passed the audition.

 I loved to sing, especially to Beatles tunes, which I played on the hi-fi in our living room at home. However, being part of the school choir was anything but fun. Unlike my beloved grandmother, the choir director was stern and impatient; a flubbed lyric or missed beat elicited her immediate rebuke. It was only at the biannual concerts for our parents — one before Christmas and one in the spring — that we saw her smile.

 Then, when I reached fifth grade, everything changed. Our drill-sergeant choir leader retired and was replaced by an engaging new director who wore cuffed bell-bottoms and bright scarves in her hair. At our first practice, she handed out percussion instruments for all of us to play. On another day, she spun Smokey Robinson’s pop hit “The Tears of a Clown” on her phonograph. Even better, she invited us to dance, and as we did, I couldn’t take my eyes off the girl I had a crush on.

 Smokey’s voice was a distant echo as I made my way off the choral riser at the Christmas concert to perform my unplanned solo. I listened to my new choir director’s piano vamp, and then I began to sing:

 “When I was a seeker, I sought both night and day. I asked the Lord to help me …”

 Unfortunately, the Lord wasn’t much help that night; in the cavernous gym, my voice sounded as thin as a reed, and my neck muscles were taut, like cello strings. I thought I was going to faint — and then Christmas came early.

 When I reached the chorus — “Go tell it on the mountain …” — I heard a low, rich voice behind me, welcome as a life raft. As I warbled on — “over the hills and everywhere …” — I looked over to the piano. My choir director’s eyes were closed and her head was tilted back slightly, like she was singing to heaven. Her assured alto calmed me. In the second verse, I sang with more confidence. And when she syncopated a lyric as we repeated the chorus together, I felt the spark of her improvisation. At the song’s end, everyone clapped, and I took an awkward, happy bow.

 Whenever I hear “Go Tell It on the Mountain,” it brings me back to a packed gymnasium at Robert F. Kennedy Elementary School; to a hip and gifted choir director; and to my mountaintop moment as a singer — the first and only one.

 I really should have thanked my friend for getting the flu.

 John Walsh (john@walshadv.com), a monthly contributor, is a partner in the East Greenwich-based communications firm, Walsh & Associates.