Frank Vincent Zappa was born on December 21, 1940, in Baltimore, Maryland — a little over 30 miles from Annapolis, Maryland, the home of the United States Naval Academy, and about 40 miles from the Washington Navy Yard in Washington, DC: the home of the U.S. Navy Band.

Whether it was this close proximity, their sound, what they stood for, or all of the above, it’s not quite clear, but this was: Zappa — the freewheeling improvisational composer and, well, musical genius — was an enormous fan of the U.S. Navy Band, and on April 1, 1980 the mellifluous sailors recognized his earnest adoration with a surprise! as he got off a flight at the airport in San Francisco.

They played one of his signature songs, “Joe’s Garage.”

The impromptu event (captured in the following footage) was unearthed earlier in the year when a documentarian, working on a film of Zappa’s life, was given access to archives previously held in private by Frank’s family. He released the snippet as part of an attempt to raise funds for the project.

From Rolling Stone:

“I’ve been looking at a lot of previously unknown or little-seen archival of Frank, and this one was particularly powerful to me for two reasons,” the documentary’s director, Alex Winter, tells Rolling Stone. “The first is that Frank was so rarely himself in public. He was a master showman, performer, orator, wit, political pundit, etc. In this clip, Frank is genuinely and profoundly moved by the band’s performance of his music, and so we get to see him unprepared and just being himself.

“The other reason I love this piece is to watch it from the other side: the joy, concern, nervousness and reverence of these musicians, doing a fantastic job of playing a difficult piece for the notoriously discerning composer,” he continues. “At the end of the day, it’s all about the power of music. And Frank’s wonderful music in particular.”

Zappa himself liked the clip so much that he duplicated the master onto his own tapes so he could preserve it.

The “definitive” documentary of the “Mothers of Invention” bandleader is set to be released in 2018.