Julz Sale, co-founder and singer of Delta 5, whose 1980 indie hit “Mind Your Own Business” saw an unexpected revival when it was used in an Apple ad earlier this year, has died, Variety has confirmed via the band’s U.S. label. Her age and the circumstances of her death had not been announced at the time of this article’s publication.

Sale (pictured above, center, circa 1980) later worked at the Rough Trade record label in the U.K., which paid tribute to her on social media Wednesday. The label had released all of the band’s material in the U.K.

“We are very sad to learn of the passing of Julz Sale, Delta 5 founding member and former employee of the Rough Trade label,” the post reads.

“Mind Your Own Business” was the first single by Delta 5, which grew out of the late ‘70s Leeds University art-school scene that spawned post-punk luminaries like Gang of Four and the Mekons. Unusually, the group had two bassists, and the song is built around a driving beat, throbbing bassline (oddly reminiscent of the Slits’ cover of “Heard It Through the Grapevine,” released around the same time), stabs of grating, Gang of Four-like guitar and chanted, in-your-face vocals. The group achieved some indie acclaim in the U.K. and U.S., but split in 1981 after a lukewarm response to its debut album, “See the Whirl.”

However, the song and the group acquired a cult following over the years, with a handful of indie covers and occasional airplay on alternative radio, and a compilation was released in 2006 on the long-running indie label Kill Rock Stars — which is essentially how the song landed in Apple’s “Privacy on iPhone” ad, which debuted in May and aired regularly throughout the spring and summer. A rep for the band’s U.S. label, Kill Rock Stars, confirmed to Variety that the band holds the song’s copyright, approved the use and “they will be getting paid.”

Kill Rock Stars also issued a statement on Wednesday. “Julz Sale’s contribution to punk, post-punk and music at large will be felt forever,” it reads. “We are gutted by the news of her passing. She was a delight to know and will be missed immensely. We encourage each of you to listen to Delta 5 for the remainder of the week and/or month.

Variety will have information as it becomes available.