In 1972, David Bowie introduced the world to his Ziggy Stardust persona with a performance on the British television show Lift Off With Ayshea. Footage of this TV debut has long been considered lost, since Lift Off’s tapes were accidentally wiped when they were sent to be digitized. But archivists have just unearthed a fan’s home video recording of the show.

The tape has degraded over the decades, so archivists are attempting to restore it by “baking” it in an incubator. If it’s restored in time, the long-lost footage may feature in next month’s BBC2 documentary, David Bowie: Finding Fame.

“For fans, it is something of a Holy Grail,” Francis Whately, producer and director of the documentary, told the Radio Times, via the BBC. “It would fall apart if we played it, so it’s had to be very carefully restored. It will be a real coup if it comes off.”

Restoration is still in progress, and will continue until very close to the documentary’s air date.

“The footage has only very recently been discovered,” said a BBC spokeswoman. “We’re hoping it will be ready in time to include in the film.”

Finding Fame is the third in Whately’s trilogy of films about Bowie. The 90-minute documentary will feature previously unheard recordings by Bowie, including a 1965 BBC audition with his band the Lower Third performing “Chim-Chim-Cheree” and “Baby, That’s a Promise.” At the time, the BBC famously rejected the singer, saying he was a “cockney chap but not outstanding enough” and “devoid of personality.”

Before this new discovery, the earliest available Ziggy video was Bowie’s watershed performance in a snakeskin jumpsuit on Top of the Pops, which took place a month after the Lift Off show.