Joni Sledge of Sister Sledge appears on stage at the amfAR's 23rd Cinema Against AIDS Gala at Hotel du Cap-Eden-Roc, Cap d'Antibes, France, May 19, 2016. Getty Images

Joni Sledge, a founding member of the vocal group Sister Sledge, died Friday at the age of 60, a statement from the band said. Popular for records such as "We Are Family," "He's the Greatest Dancer," "Frankie" and more, the group was formed in 1971.

Sledge was found dead in her home in Phoenix, Arizona, by a friend, the band’s publicist Biff Warren said Saturday, according to the Guardian. A cause of death has not been determined.

“Yesterday, numbness fell upon our family. Pray for us as we weep for the loss of our sister, mother, aunt, niece and cousin Joni Sledge. We thank you for privacy as we hurt for her presence, but also for embracing her radiance and the sincerity with which she loved life," a statement issued by her family said.

Sledge was the second eldest sister in the hit pop group, which also has Debbie, Kim and Kathy.

“The four of us had been in the music business for eight years and we were frustrated. We were saying: ‘Well, maybe we should go to college and just become lawyers or something other than music, because it really is tough,’” Sledge told the Guardian in an interview in 2016.

The Philadelphia-born never usually sang the lead in the group, but did so on the popular song "Reach Your Peak."

The group's "We Are Family" reached No. 2 on the Billboard Hot 100 and became an international hit. The album's disco jam "He’s The Greatest Dancer" became a top 10 hit in May 1979. The album sold more than 1 million copies and received a Grammy nomination.

Rock and Roll Hall of Famer Nile Rodgers, who co-wrote "We Are Family" with the late Bernard Edwards of Chic, remembered Sledge on Twitter.

Sister Sledge was scheduled for a show on March 18 and a series of European performances was planned.