The following story is courtesy of Jem Aswad from MTV.com:

ISAAC HAYES - a legendary soul singer, songwriter, musician and producer whose career spanned four decades and who achieved unexpected fame later in life as the voice of "South Park" character Chef - died Sunday afternoon (August 10), a spokesperson for the Shelby County, Tennesee, sheriff's department told WMC-TV in Memphis.

Hayes' wife found him on the floor near a treadmill inside his home, according to the station's Web site. Hayes was taken to Baptist East Hospital in Memphis, where he was pronounced dead at 2:08 p.m.

Deputies with the Shelby County Sheriff's Department are continuing their investigation into Hayes' death, but they believe no foul play was involved, the report said. Hayes was 65.

Born in Covington, Tennessee, in 1942, Hayes was a key figure in the development of the 1960s Southern soul sound before going on to a successful solo career.

He made his public singing debut in church at the age of 5, and taught himself piano and saxophone before relocating to Memphis and performing with groups there, according to All-Music Guide. In 1964, he began playing with the MAR-KEYS, which led to his long stint as a musician, songwriter and producer for the legendary Memphis soul label Stax Records.

Over the following years, Hayes and songwriting partner David Porter wrote a reported 200 songs, including such soul classics as SAM & DAVE's 'Soul Man' and 'Hold On, I'm Comin'', CARLA THOMAS' 'B-A-B-Y' and JOHNNIE TAYLOR's 'I Had a Dream'.

Hayes released his debut solo album in 1967, but his breakthrough came two years later with the classic Hot Buttered Soul, which featured lush, ambitious arrangements and an innovative structure, and exerted a profound influence on many soul albums to come — not least MARVIN GAYEs What's Going On.

In 1971, Hayes reached the peak of his musical popularity with the single and album Shaft, the score from the film. The song not only was an archetypal slice of funk that garnered Hayes a #1 single and Grammy and Academy Awards, the talk-singing style he employed on it exerted a huge influence on rap music.

Read more here.

'Shaft' live: