The Duke of Sussex and Boris Johnson have had an informal "catch-up" chat behind closed doors just hours after Prince Harry said he had "no other option" but to step back from royal life.
Prince Harry carried out what is likely to be one of his few remaining official engagements before the Sussexes take a "leap of faith" and leave the monarchy for a new life in Canada.
He and the Prime Minister met for 20 minutes one-to-one without any aides present at the UK-Africa Investment Summit.
Looking relaxed and wearing a suit, shirt and tie, the duke arrived at London's Docklands where Mr Johnson was hosting the global event on Monday.
The Duke of Sussex delivered a speech on Sunday night where he told the "truth" about leaving royal duties behind in a bid for a "more peaceful life" for his family.
Boris Johnson meanwhile set out his post-Brexit trade pitch to African leaders with his vision to put "people before passports" in an immigration system overhaul.
The Prime Minister was tempting premiers from across the continent with the UK's financial and education systems as he opened his investment summit in London's Docklands on Monday.
He also announced an end to UK support for thermal coal mining or coal power plants overseas in a bid to use trade to tackle the climate crisis.
With the EU departure coming on January 31, Mr Johnson was pledging to be a partner "through thick and thin" with African nations as he eyes fresh trade deals across the globe.
And - at the summit also attended by the Duke of Sussex - the PM made a pitch for improved business links from his proposed Australian-style immigration system.
"Change is coming and our system is becoming fairer and more equal between all our global friends and partners, treating people the same, wherever they come from," he told the UK-Africa Investment Summit.
"By putting people before passports, we will be able to attract the best talent from around the world, wherever they may be."
Mr Johnson gave current partnership examples of Nigerian street lights being stocked with low-emission diodes from Dorset, and Angolan families tucking into chicken from Northern Ireland.
"We want to build a new future as a global free-trading nation, that's what we will be embarking on on January 31," he said.
"But I want to intensify and expand that trade in ways that go far beyond what we sell you or you sell us.
"I've just told President (Yoweri) Museveni of Uganda that his beef cattle will have an honoured place on the tables of post-Brexit Britain."
Mr Johnson also spoke of the climate crisis and fight to save biodiversity by ending direct official development assistance, investment and export credit as part of his coal plan.
"There's no point in the UK reducing the amount of coal we burn if we then trundle over to Africa and line our pockets by encouraging African states to use more of it," he said.
"To put it simply not another penny of UK taxpayers' money will be directly invested in digging up coal or burning it for electricity."
Mr Johnson was meeting presidents from Rwanda, Ghana and Nigeria at the summit, and was due to have talks with the premiers of Egypt and Kenya at Downing Street on Tuesday.
The Duke of Sussex's attendance comes after he said there was "no other option" but for him and wife Meghan to stand down from the royal family.
It emerged the couple had wanted to remain as working royals, although not prominent members, and drop their public funding so they could become financially independent - a dual role many commentators said was fraught with problems.
But in a statement issued on Saturday after Royal Family talks concluded, the Sussexes announced they will stop carrying out royal duties from the spring, no longer use HRH and will repay the taxpayers' millions spent on their Berkshire home.
Critics have accused the couple of turning their backs on the monarchy in order to enjoy the freedom that being able to take on commercial ventures brings.
In a speech at a private event for his charity Sentebale on Sunday night in London, Harry told invited guests: "What I want to make clear is we're not walking away, and we certainly aren't walking away from you.
"Our hope was to continue serving the Queen, the Commonwealth, and my military associations, but without public funding. Unfortunately, that wasn't possible.
"I've accepted this, knowing that it doesn't change who I am or how committed I am.
"But I hope that helps you understand what it had to come to, that I would step my family back from all I have ever known, to take a step forward into what I hope can be a more peaceful life."
The duke was not officially attending the summit but was holding audiences - one-to-one meetings - with a number of foreign leaders at the request of the UK Government.
Harry sat down to talks with Saad-Eddine El Othmani, prime minister of Morocco, Peter Mutharika, president of Malawi and Filipe Nyusi, president of Mozambique.