By Alastair Leithead
BBC News, Johannesburg
Nelson Mandela's decision to announce that his son died of Aids will send out a strong message in a country where stigma and denial still surround the virus.
More than 600 people are thought to die every day in South Africa of Aids-related illnesses and millions are HIV-positive.
Nelson Mandela is still idolised by millions of South Africans
But still people would rather say relatives died of TB rather than Aids - the most common opportunistic infection to kill those living with the virus.
At the many funerals held every weekend, people often do not speak out about the cause of death - Aids is still something of a taboo.
And President Thabo Mbeki has had controversial views - he once said he did not know anybody who had died of Aids and appeared to question the link between HIV and Aids.
There has been criticism that the government did not act quickly enough to help treat people with the virus, and that it still sends out mixed messages over HIV/Aids.
Anti-retroviral drugs are now being rolled out around the country, but treatment campaigners say it is still not happening quickly enough.
But for Nelson Mandela to speak so frankly about the virus and its effect on his family will make many people sit up and listen - and perhaps do as he asked and be more open about the disease.
There is still a lack of political will to emphasise just how serious the HIV/Aids pandemic is
It is hard to overestimate the iconic status Nelson Mandela still has in this country, the grip he has over people - and, therefore, the impact his announcement will have.
Surrounded by close friends and family, he made it clear that the best way to fight stigma and denial is to be open and honest about the virus.
He said he began a campaign more than three years ago to raise awareness about Aids, not knowing it would affect him in such a personal way.
Pressure on Mbeki
The former president has at times been an outspoken critic of the government in his campaigning.
There is the feeling here that although the government has gone a long way in the past few years to prevent and to treat the virus, there is still a lack of political will to emphasise just how serious the HIV/Aids pandemic is from people such as President Mbeki.
Health care for Aids sufferers has improved in South Africa
He says little on the subject, and statements from his Health Minister Manto Tshabalala-Msimang about the value of garlic, the African potato and traditional healers in treating the virus have been criticised for causing confusion.
Nelson Mandela's public statement will continue to pressure Mr Mbeki, especially as it follows a similar admission from another veteran South African politician, Mangosuthu Buthelezi, who has lost two of his children to Aids.
As Nelson Mandela said, the only way to break down the barriers surrounding the virus is to speak about it publicly, and doing so in such a personal way can only help raise awareness further.