Joni Sledge, the singer best-known for the disco anthem We Are Family, has died aged 60.
Sledge, who formed Sister Sledge with her three siblings in 1971, was found unresponsive by a friend at her home in Phoenix, Arizona, her publicist said.
She had not been ill and the cause of death is unknown.
Sledge, who is survived by her adult son, last performed with the band in October.
Her death was announced on social media on Saturday – a week before the group were due to perform in Los Angeles.