William ‘Poogie’ Hart died age 77 from “complications from surgery”.
The Delfonics frontman passed away unexpectedly, with TMZ reporting the cause of death as linked to a medical procedure.
It is understood the singer had been struggling with breathing and was rushed to Temple University Hospital, Philadelphia.
Born January 14, 1945, William and his brother Wilbert were the founding members of the Delfonics in the late 1960s.
Their bandmates included Randy Cain, Ritchie Daniels, and Thom Bell, with William and Thom writing their entire catalogue.
The Delfonics split in 1975 after landing a dozen top-20 hits on the ‘Billboard R B and Soul Single Chart’.
Former members continued to perform in other bands throughout the 1990s and 2000s, with crowd-pleasing songs including ‘Didn’t I’ and ‘La-La (Means I Love You)’ – which featured in the soundtrack of Quentin Tarantino’s film ‘Jackie Brown’.
Directors such as Spike Lee have used their music, with their songs widely covered by other acts.
Biggie Smalls, Missy Elliott and Nicki Minaj have sampled their tunes, while The Fugees played a version of The Delfonics’ ‘Ready Or Not, Here I Come (Can't Hide From Love)’ on album ‘The Score’.
Delfonics fans flooded the web with tributes, with one saying about how they inspired a raft of other groups: “There’s no Blue Magic, no Stylistics, or any other group that excelled in ballads in the early 70s (especially groups that had a primary falsetto lead singer) without the foundation of The Delfonics. RIP William Hart, now reunited with Randy Cain and Major Harris.”