The opening notes of Strauss’s “Also sprach Zarathustra” feel irreplaceable over the title sequence of Stanley Kubrick’s 2001: A Space Odyssey. However, finding the right music for the film wasn’t as simple as you might expect. Even for the iconic opener, Kubrick originally commissioned veteran film composer Alex North, before notoriously ditching his score for the classical work.

Now, more than 50 years after the original release of 2001, another rejected track has made an appearance. Written by Kubrick’s long-time publicist, Mike Kaplan, the “lost” song is titled “2001: A Garden of Personal Mirrors”. 

The filmmaker turned to Kaplan to write the song after turning down other promotional music, the publicist remembers in a recent interview with the Observer. Kubrick felt he understood the message behind the film, he says, and said: “I hear you write music. Why don’t you write something?”

“The single’s intent was to capture the different responses 2001 was generating from audiences and the media, the many levels of interpretation and appreciation, from its hypnotic visuals to its metaphysical illuminations,” says Kaplan in a statement on the track. “We also wanted to instil curiosity among audiences who had not yet seen what was becoming a cultural phenomenon.”

Though Kubrick apparently liked the track, which incorporated vocals from folk performer Naomi Gardner, he couldn’t see it becoming a hit. Though he and Kaplan continued to work together, including on A Clockwork Orange, they never discussed the song again. As a result, “2001: A Garden of Personal Mirrors” had to wait more than half a decade to see the light of day, following its release via the UK-based label Wave Theory Records.

In recent years, several other remnants from Stanley Kubrick’s career have been unearthed, including a Burning Secret screenplay, three script ideas tackling jealousy and adultery, and an unfinished Clockwork Orange sequel.

Listen to the newly-released “2001: A Garden of Personal Mirrors” below.