Prince Harry has called for more to be done to combat HIV/Aids as he kicked off an energetic Coldplay set during his charity concert.
He said the disease "thrives off silence and feeds on stigma".
In his speech to the 3,000 strong crowd at Kensington Palace, Harry said: "Tonight you've been learning a little bit about Lesotho, a beautiful mountain kingdom I first travelled to when I was 19.
"What I saw there was a country with significant challenges; some of the world's most vulnerable young people, robbed of their childhoods."
He said: "In some cases the 'lady of the house' was a 12-year-old girl looking after her brothers and sisters.
"But what I remember most from that first visit was learning that this was a country with joy in its heart - a country that faced its challenges with warmth, optimism and courage. It didn't take me long to be hooked on the country and to the irresistible smiles of its children."
Headlined by Coldplay, the Sentebale concert raised funds for children with HIV/Aids in sub-Saharan Africa.
The charity provides psychosocial care for young people with the disease to help educate them and give them support.
Harry continued: "Sentebale has helped tens of thousands of children in just over a decade. This is a topic that has drifted from the headlines, but remains an urgent challenge.
"What we know is that HIV is a virus that thrives off silence and feeds on stigma.
"Every single one of us has a responsibility to educate ourselves.
"To do what we can to speak out and stamp out the silence, ignorance and fear that the virus needs to win."
Harry set up the charity after his gap year to Lesotho in 2004.
The country's Prince Seeiso, younger brother of King Letsie III, and Harry established Sentebale in memory of their mothers.
Sentebale means forget me not, which Harry later found out was his mother Diana, Princess of Wales's favourite flower growing up.
Other performers who entertained the crowds included Joss Stone, Laura Mvula and spoken work artist George the Poet.
The event was hosted by ITV's Tom Bradby. Coldplay performed fresh from Glastonbury, pleasing the crowd with favourites Paradise, Clocks and Fix You.