The duke is hosting the Rugby League World Cup 2021 draw at Buckingham Palace and will remain in the UK into next week.
Prince Harry is carrying out his first public engagement since announcing last week he and wife Meghan will be stepping back as senior royals, sparking a royal crisis.
The Duke of Sussex is at Buckingham Palace where he is hosting the Rugby League World Cup 2021 draw and meeting representatives from all 21 participating nations.
He also spoke to children from a local school who were playing rugby in the palace gardens and gave them a thumbs-up.
The prince jokingly told the youngsters to “look after the grass or I’ll get in trouble”.
Harry was also introduced to two ambassadors for the global tournament – James Simpson, England and Leeds Rhinos wheelchair rugby league star, and Jodie Cunningham, a rugby league player in the Women’s Super League for St Helens.
Mr Simpson made Harry laugh when he said “we started without you”.
The prince also posed for a group photograph with the children, and one reporter asked: “How are the discussions going on your future?”
Harry smiled at one of his entourage and did not reply.
The World Cup will take place in October and November next year in 17 cities across England, with 16 men’s, eight women’s and eight wheelchair teams competing.
Harry has also backed the tournament’s decision to adopt a mental health awareness programme, including workshops for 8,000 young players.
He said in a video: “This charter will build on the brilliant work already happening in rugby league by committing to training and educating all those involved in the tournament.”
Harry will remain in the UK into next week, despite rumours he was preparing to fly to Canada to join Meghan and their eight-month-old son Archie.
On Monday, the Queen – in a bid to take back control of the situation – approved of Harry and Meghan’s desire to step back from their royal duties, as well as split their time between the UK and Canada and become financially independent.
The backing came after face-to-face talks between Harry, his grandmother the Queen, his father Prince Charles and his brother Prince William.
Harry was reported to be staying in the UK to hold further discussions about his future role in the Royal Family.
The Duchess of Sussex is in Canada with Archie, who is said to have stayed there with a nanny when she and Harry travelled to the UK.
On Tuesday, Meghan visited a women’s shelter in Vancouver to discuss issues that impact women directly – her first engagement since last week’s announcement.
On Wednesday, the duchess visited the charity Justice For Girls to discuss issues including the rights of indigenous peoples and the power of young women’s leadership.
But while Meghan has been warmly welcomed by those she has been pictured with in Canada, one of the country’s biggest newspapers has said she and Harry should not be allowed to make their move permanent.
An editorial in The Globe and Mail urged Canadian PM Justin Trudeau to deny any residence bid by the couple, saying: “Canada is not a halfway house for anyone looking to get out of Britain while remaining a royal.”