Gloria Bongekile Ngema will become Zuma's fourth wife after having been engaged to him for a number of years.

Zuma's spokesman, Mac Maharaj, confirmed yesterday: "The president is to formalise his relationship with his fiancée, Ms Bongi Ngema, next week at a private traditional ceremony in Nkandla."

Zuma has a three-year-old son with Ngema. He reputedly has about 20 children in total.

Last year, Ngema joined Zuma on a diplomatic trip to France, her first state visit. The privilege is usually reserved for the first lady.

Hailing from Durban's Umlazi township, Ngema was described as devoutly religious by friends in a Sunday Times profile story two years ago. She has various academic qualifications, including a business degree.

But she may be the last bride Zuma takes. At a lavish birthday bash in Durban on Friday evening, more than 1000 guests watched a video montage in which he said his marrying days were over.

He turned 70 on Thursday and has married twice during his presidential term.

Zuma's other wives are Sizakele Khumalo, whom he met in 1959, Nompumelelo "MaNtuli" Zuma and Thobeka Stacey Mabhija.

He divorced Home Affairs Minister Nkosazana Dlamini-Zuma in 1998, and another wife, Kate Zuma, committed suicide two years later.

Zuma was born into a polygamous family. His father had two wives, Zuma's mother being the junior.

Yesterday, Nkandla locals were in the dark about the nuptials. Even close family members expressed surprise.

The homestead, which has undergone a massive R64-million renovation, hosted a second birthday party yesterday. The renovations included the construction of six double-storey thatch rondavels for Zuma's wives and family.

A guest with knowledge of the compound said the buildings were ready to be handed over to the wives. The sixth one is still being built.

He said there was 32mm armoured glass in the windows.

Sunday Times has reliably learnt that each of the main bedrooms were connected to Zuma's main house by underground tunnels.

The president acknowledged his wives : "I have them; they are many. They know that who comes in does not close the door behind [her] because it was not shut behind her."

Ngema and Zuma's other three wives were all on hand to cut his R12500 birthday cake at the International Convention Centre on Friday. The celebration was organised by his daughters.

Political heavyweights, diplomats and top businessmen, including billionaire Patrice Motsepe and his wife, Precious Moloi, attended.

Also there were government spokesman Jimmy Manyi and his wife, Stella; South Africa's high commissioner in London, Zola Skweyiya, and his wife, Thuthu; KwaZulu-Natal MEC for economic development Mike Mabuyakhulu; Minister of Finance Pravin Gordhan; sports administrator Danny Jordaan; and Durban businessman and ANC funder Vivian Reddy.

Among the traditional items on the menu were pickled ox tongue with chakalaka, braised lamb shank stew, samp and beans, amadumbe (potatoes) and mieliepap. Guests were treated to boxes of chocolates and personalised bottles of water.

Zulu King Goodwill Zwelithini supplied his signature wine, Bayede, a huge bottle of which went to Zuma as a gift.

Intimate details of his personal life were revealed when guests were shown video clips of 70 questions put to him by his daughters.

He disclosed that he would happily go on a date with DA leader Helen Zille and that his first car was a used Ford Cortina.

Asked if he was done with marriage and children, he answered "I think so" to the first and "Yes" to the second. And how does he like his women? "I like one with some body."