On the eve of President Jacob Zuma's State of the Nation address, it emerges that he has two daughters, aged 12 and 7, with prominent Pietermaritzburg businesswoman Nonkululeko Mhlongo.
The Mercury was tipped off about the existence of the two members of the presidential progeny during the public controversy that flowed from the news that Zuma had fathered a baby in October last year with his lover, Sonono Khoza, the 39-year-old daughter of soccer tycoon Irvin Khoza.
The birth came four months before his traditional marriage to Thobeka Madiba with whom he has three children.
While the president apologised on Saturday in the face of mounting criticism and heated debate about his morals and fitness to hold office, the latest revelation puts another damper on the Union Buildings efforts at damage control ahead of the all-important State of the Nation address today.
A presidential aide said yesterday that there was "nothing new about Mhlongo and her kids".
"They are part of the 20 children and have always been. The eldest even attended her dad's inauguration. There is nothing secret or sensitive about her. What is the hullabaloo about?"
The aide added: "The kids have always been part of the extended family. JZ doesn't hide his kids."
The daughters, whose names are known to The Mercury and who attend a top school in the KwaZulu-Natal capital, were born on January 18, 1998, and September 19, 2002.
The president's relationship with Mhlongo, 49, spanned a period when his personal life was in turmoil, during which his second wife, Nkosazana Dlamini-Zuma, divorced him in June, 1998, and his third wife, Kate, committed suicide in December, 2000.
At the time his first child with Mhlongo was born, Zuma was a KwaZulu-Natal MEC, and when their second daughter was born, he was deputy president and the head of the country's moral regeneration movement.
At the same time he was also in a relationship with Nompumelelo Ntuli, with whom he had two children - now aged eight and four - and whom he later married, in 2008.
The fact that Zuma had children with Mhlongo is an open secret in the KwaZulu-Natal legislature, although no one was prepared to comment on the record, saying the matter was sensitive.
Mhlongo, who recently opened an upmarket restaurant in the Pietermartizburg CBD, had a lucrative contract with the legislature, providing MPs with meals during committee meetings and sittings.
While there is no suggestion that Mhlongo's relationship with the president helped secure the catering contract, some sources in the legislature were concerned that such an inference would be drawn if The Mercury went ahead and published the story.
"The next thing people will want to link her business operations and acquisition of contract to her relationship with the president whereas she has been conducting her business legitimately," said one source.
Like Khoza, who refused to be drawn into media speculation, Mhlongo was not prepared to confirm her relationship with the president, claiming she did not know him and denying he was the father of two of her four children or that she was divorced.
According to official records, however, she divorced in 2006.
"I have seen him in rallies and on television but have never gotten closer than that," Mhlongo said.
Presidential spokesman Vincent Magwenya declined to answer a list of specific questions, and would only say: "These are not questions for the presidency to answer."