Joni Sledge, one of the voices behind Philadelphia-founded disco faves Sister Sledge, passed away Friday at her home in Arizona. She was 60 years old.

An announcement last night on the band’s official Facebook page had this to say.

Yesterday, numbness fell upon our family. We are saddened to inform you that our dear sister, mother, aunt, niece and cousin, Joni passed away yesterday. Please pray for us as we weep for this loss. We do know that she is now eternally with Our Lord. We thank you in advance for allowing us the privacy to mourn quietly as a family. We miss her and hurt for her presence, her radiance, and the sincerity with which she loved & embraced life.

The sisters Kim, Debbie, Joni and Kathy founded the group in 1971, after honing their skill as singers at the Williams Temple Christian Methodist Episcopal church in the Greys Ferry section of Philadelphia. They performed across the 70s and connected with Bernard Edwards and Nile Rodgers of Chic later in the decade, riding the disco wave to big success.

Of working with Edwards and Rodgers, Joni had this to say in a 2016 piece in The Guardian:

It was fun, but challenging. Bernard and my sister Debbie were both musical geniuses when it comes to harmony, chording, things like that, and in the studio, they were like, “Grrr!” Nile was the mediator. One day in the studio they both walked out, and Nile was like, “All right, OK, everybody take a break. I’m going to talk to Debbie.” They would bicker and he was the vicar!

The work resulted in the massive 1979 hit “We Are Family,” which topped the R&B and disco charts that year, and also rose to number two on the Billboard 100. As Joni tells it:

Recording the track We Are Family was like a one-take party – we were just dancing and playing around and hanging out in the studio when we did it – but Lost in Music was totally different. It was like being in a trance. Even when we play it today, it’s different every time we do it. We have brilliant musicians, and we just say, “Take us somewhere. Go deep,” and we let the audience know, “You know what? Come along if you want to, but they’re really going to take us somewhere!” And they do.

The song was Sister Sledge’s biggest hit — it’s still a staple at weddings — and gave them their most successful LP. The band appeared on Soul Train on several occasions across the 70s, and is also known for singles like “He’s the Greatest Dancer,” “Love Don’t Go Through No Changes on Me” and “Frankie.”

Joni Sledge continued performing with her sisters across the 80s and 90s, and into the 00s — Kathy formally left the band in 1989, but occasionally joined them for one-off shows.

Joni is survived by her son, Thaddeus, and sisters Debbie, Kim and Kathy. Watch videos of Joni Sledge performing with Sister Sledge in the 70s below.

(h/t Billboard, The Guardian)