It was a cause close to his late mother's heart, and now Prince Harry has followed in Diana's footsteps with his contribution to a documentary about Aids in Africa.
The half-hour programme, The Forgotten Kingdom: Prince Harry In Lesotho, was made during the 19-year-old Prince's gap year trip to the African country earlier in the year.
"It's not a place that everybody really knows about," explained Harry, speaking during a visit to a children's home in the capital Maseru.
Around 40 per cent of Losotho's population is thought to have HIV or Aids, while life expectancy for men is just 32, and 38 for women.
It is hoped the documentary, which includes footage shot by the Prince - who also helped produce it - will raise £250,000 for youngsters suffering from the illness.
The programme is expected to air on ITV1 in October.