Quinshae Snead was on her way to Ashanti's hotel to pick up something for the Grammy award-winning singer before her Saturday concert when the accident occurred.
According to police, the 20-year-old was a passenger in a car that was rear-ended.
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 suspect was driving without a license and had stolen his mother's car, according to Johannesburg metro police spokesman Chief Superintendent Wayne Minnaar.
The teenager was arrested for drunken driving and hospitalized.
The driver of the car Snead was in was also injured and taken to hospital.
Ashanti will escort her cousin's body back to the U.S.
