South African police said the couple were returning from dinner in Somerset West, near the town of Stellenbosch, when two armed men stopped the car.
After forcing the driver out, the men drove off fromthe township of Guguletu – which is 15 kilometres outside Cape Town – with the couple in the car.
At around midnight, an hour later, the 31-year-old husband was dropped off in the Harare area of the Kyayelitsha, while the men drove off with his wife, aged 28.
“After seeking the assistance of a passing motorist, he was taken to Harare police station unharmed,” South African police said in a statement.
Following an extensive search the abandoned car – a Volkswagen Sharan – with later found by police with the body of the wife in the back seat.
Police have yet to make any arrests, with the two armed men still on the run.
They would not comment on how the woman died, adding that an autopsy would need to be conducted.
The couple, who married two weeks ago, arrived in Cape Town last Thursday.
Tammy Evans, spokeswoman for the province’s tourism MEC, said: “We are obviously devastated from tragedy. We have had no incidents from the World Cup up until now.”
A spokesman for the British High Commission in Pretoria added: “We are aware of the situation…and we’re offering consulate assistance. We cannot give out any information about the couple…it will be up to the family whether to release details or not.”