Ashanti pulled out of a concert over the weekend after her cousin was killed by a 17-year-old drunken driver, authorities said.
Quinshae Snead, 20, was on her way to Ashanti's hotel to fetch something for the Grammy award-winning singer ahead of the concert Saturday when the car she was riding in was rear-ended, police said.
Snead was flung from the car as it rolled over and thrown into the path of another car in the opposite lane.
The 17-year-old unlicensed driver had stolen his mother's car, said Johannesburg metro police spokesman Chief Superintendent Wayne Minnaar.
"He was also under the influence of liquor," Minnaar told the South African Press Association.
The teenager was arrested for drunken driving and hospitalized. The driver of the car Snead was riding in also was injured and taken to hospital.
Ashanti's debut album garnered a Grammy Award in 2003 for best contemporary R&B album.