Prince Harry listened intently this afternoon as young people from Lesotho and Botswana spoke about the stigma of living with HIV.
The Prince told them it was "absurd" that young people don't hear about the disease until it's too late.
Tlotlo Moilwa, who is 18, described to Prince Harry how she lost both her mum and dad to the condition when she was just four years old.
The Prince's charity Sentebale brought Tlotlo, who's from Botswana, and others to London to speak to the world's most influential experts on HIV and AIDS.
Prince Harry said: "To me, it is totally absurd in today’s world that for young people the first time they hear anything about HIV and AIDS, it’s probably by the time it’s too late."
Ts'epang Maboee, from Lesotho, lost her father when she was just one and her mother when she was 10. She herself tested positive for HIV four years later.
They all spoke about the difficulty of publicly sharing their HIV status in order to help counter the stigma which surrounds the condition.
Ts'epang told Prince Harry how many of those in their early teens have sex with older men in order to get money and later test positive for HIV.
Sentebale runs various clinics in Lesotho and Botswana - countries where health services are scarce.
The Prince took notes as he heard how young people are reluctant to attend the few clinics which exist because adults are treated in the same room as teenagers.
Prince Harry spoke at the start of the session, saying: "Whether it’s in the education system here in the UK, whether it’s across Africa or across the world, HIV needs to be treated exactly the same as any other disease.
"Between us we can hopefully eradicate the stigma and give these young people the opportunity to stand and say 'I’ve lived it, I’ve breathed it and you know what? I’m going to make a difference because I don’t want anybody else my age to go through exactly what I went through'."
Kananelo Khalia, also from Lesotho, told the Prince how both his father and younger sister died of HIV. He tested positive himself in 2007.
Kananelo suffered what he described as "stigma and hostility" from his peers.
But he said he had a vision of "keeping the next generation alive" and letting his fellow sufferers know "there is still life after being tested positive".
Harry's mother, Princess Diana also worked with AIDS charities and was one of the first high profile people to be pictured touching those with AIDS.