Well-known farmer and wine-maker Anthonij Edward Rupert, 49, the youngest son of businessman Anton Rupert, has died in a car crash.
Rupert's BMW 740i was found overturned on the Simondium Road in Franschhoek, said William Reid of the Boland police.
He said it had been raining heavily, but the exact circumstances of the accident were unknown.
Family publicist Frans Stroebel said Rupert was known in international wine circles and had established a joint venture with the Derothchild family of France in 1997.
They produced wine under the name Rupert Rothchild on Rupert's farm, Fredericksberg.
Rupert is survived by father Anton, mother Huberte, brother Johan and sister Hanneli. He was not married.
A memorial service is to be held at 3pm on Tuesday at the Dutch Reformed Church in Simondium.