Angelo Massagli and Caitlin Hale met as co-workers. They were 10 years old.

The pair, former child actors, were both cast in the 2003 film “School of Rock” in which Jack Black plays a substitute teacher who creates a rock band out of his classroom of musically gifted elementary-aged prep schoolers. Ms. Hale’s character was a braided pigtail-wearing backup singer named Marta. Mr. Massagli played Frankie, who was part of the band’s peewee security detail.

Mr. Massagli recalled being spontaneously asked to sing at his audition for the film in New York City. He was nervous to perform after Ms. Hale, who had just impressed the production team with her voice, including a rendition of “Everything’s Coming Up Roses” in which she changed the lyrics to be about the film’s director.

“I was like, ‘wow, that girl’s really, really, really something else,’” Mr. Massagli said. He performed the only song he knew the words to at the time: “Crazy Train” by Ozzy Osbourne.

A year later, the pair and the other children cast in the film spent several months shooting the movie in New York. The group bonded quickly, Ms. Hale said, attending real school on set and having meals at Benihana. Mr. Black, the film’s adult star, would eat lunch with the group and play games between scenes. Their moms, often present on set, also became close during this time.

Back then, there was not even a hint of a youthful crush between them, the couple said. After the film’s release, the cast stayed in touch through a long-running group chat.

Eventually, Mr. Massagli and Ms. Hale both left show business to pursue other careers.