The Duke and Duchess of Cambridge arrived at a reception at Buckingham Palace to mark the UK-Africa Investment Summit.
William and Kate were joined by other royals at the event, which followed a day of meetings for the prime ministers and presidents attending the UK-Africa Investment Summit staged in London.
Also at the event were the Earl and Countess of Wessex and the Princess Royal, who mingled with the heads of state and government and their partners, Boris Johnson and UK and African business figures.
The summit aims to demonstrate the strength of the relationship between the UK and Africa, showcase and promote the breadth and quality of investment opportunities across Africa, and highlight the UK's commitment to supporting economic development in Africa.
It is the first reception that William has hosted alone- part of his preparation to one day become king.
The Queen and Prince Charles will not be in attendance at the reception.
It comes after Prince Harry gave an emotional speech on Sunday night where he said he had "no other option" but to give up his official royal duties and forge a new life with wife Meghan and their baby son in Canada.
The Duke of Sussex said he was “taking a leap of faith” in stepping back from his life as a member of the royal family but added “there really was no other option”, during a speech at a private dinner for his charity Sentebale on Sunday evening.
He added: “Our hope was to continue serving the Queen, the Commonwealth and my military associations, but without public funding.
“Unfortunately that wasn’t possible.”
Earlier, Prince Harry carried out what is likely to be one of his few remaining official engagements when he met some of the leaders for audiences - one-to-one meetings.
He held a 20-minute meeting alone with Prime Minister Boris Johnson, it is not known as to what they discussed.
