Butho, who died on Thursday, was the son of the king’s second wife, Queen Buhle kaMathe.
Sending condolences on Friday, IFP MP Mangosuthu Buthelezi said: “I spent the greater part of yesterday with His Majesty, as condolences were expressed and the family absorbed this difficult news.
“It was agreed that the funeral should be held on Sunday at Dlamahlahla Palace, following which Prince Butho will be laid to rest in the royal cemetery in Mahashini,” Buthelezi said.
He implored the Zulu nation to keep “His Majesty and the family” in their prayers as they walk through this “painful valley of loss”.
The Premier of KwaZulu-Natal Willies Mchunu has also sent his condolences, saying: “It with a heavy heart that we received the news last night. We are shocked, but also very saddened by the news of the Prince’s sudden passing.
“On behalf of the government and people of KwaZulu-Natal, we wish His Majesty all the strength in this hour of pain and loss. We would like to extend our condolences to the entire royal family who are also hard hit by this sudden loss,” said Mchunu.
The 70-year-old king has several wives and reportedly has 28 children.
– African News Agency