Prince Harry has announced the work of his Sentebale charity supporting HIV positive young people in Africa will be expanded to a new country - Botswana.
After competing in the annual Sentebale Polo Cup, Harry told guests at the exclusive Florida event he wanted to "give as much back" as he could to the country he had visited regularly.
He also said his charity was confident of reaching the ambitious goal of providing one million hours of support to vulnerable children by 2020 - a significant increase on the 250,000 already received by youngsters since its foundation in 2006.
Harry established Sentebale, which means forget me not, in the African nation of Lesotho with its Prince Seeiso, in memory of their mothers.
The Prince revealed during a dinner speech to guests at the polo tournament, that organisers hope will raise a one million dollars (£690,000), he only discovered that day that forget-me-nots were the favourite flower of his mother Diana, Princess of Wales when she was growing up.
Harry's charity reached a major milestone last year when it opened its Mamohato Children's Centre in Lesotho - a purpose-built facility to support all of the charity's work with vulnerable children in the country, and specifically host camps delivering psychosocial support to 1,500 HIV-positive young people each year.
The Prince told the dinner guests: "This year, we are working with established partners and government departments elsewhere across southern Africa; and I'm delighted to confirm that we will be expanding our camp programme into Botswana, a country I have been visiting regularly for almost two decades and genuinely feel I need to give as much back to as I can.
"We are confident that, in partnership with others and by maximising our use of the new centre, we will provide 1 million hours of support to children and young people living with HIV and Aids across the region by 2020.
"That's an ambitious goal, but as I've already mentioned, the scale of the challenge demands bold action."
Harry also told the audience: "And incidentally I found out today that forget-me-nots were my mother's favourite flower growing up, so that's a very nice thing for me anyway."
It is understood that Harry was told the personal information about his mother by a member of the Royal Family earlier in the day.
The Sentebale Polo Cup was played in the exclusive palm tree-covered venue, Valiente Polo Farm, near Palm Beach in Florida, an area where famous names like Bill Gates, Donald Trump and Bruce Springsteen have homes.
This was the seventh time the event has been held and in past years it has been staged in places ranging from New York and Barbados to South Africa and Brazil.
Despite being staged in Florida, known as the sunshine state, the event was in danger of being washed out after the region was deluged by a series of huge thunderstorms.
Harry's Sentebale team competed against opponents led by Nacho Figueras, a professional Argentinian polo player and Sentebale ambassador, and a third team of local riders.
Figueras joked before the mini-tournament began: "Harry and I have been texting about who's going to win for days, the weather is not perfect today so whoever is better in the rain - probably him, he's English, he's used to it.''
When the Prince arrived at the palm tree-covered venue in a small town called Wellington, he held up his hands and joked: ''Welcome to the sunshine state.''
But Figueras' prediction proved right as Harry's team ended the day undefeated and claimed the cup.
Cathy Ferrier, Sentebale's chief executive officer, said: ''Great progress has been made over the past few decades to reduce new HIV infections and Aids-related deaths, however adolescents with HIV/Aids in sub-Saharan Africa remain the most at risk.
''The Sentebale Royal Salute Polo Cup is invaluable in allowing us to raise vital funds needed to support these young people, and helps us talk about an issue that urgently needs attention.''