US President Donald Trump has said Boris Johnson would make an "excellent" UK prime minister.
President Trump was speaking ahead of the start of a state visit to Britain on Monday, during which he will meet the current UK prime minister Theresa May.
Theresa May is set to resign on 7 June over her failure to deliver a deal to bring Britain out of the European Union.
Asked by The Sun newspaper for his opinion on the 12 candidates to replace her, Donald Trump said: "I think Boris would do a very good job. I think he would be excellent.
"I have always liked him. I don't know that he is going to be chosen, but I think he is a very good guy, a very talented person."
He added that several candidates in the Conservative leadership race had asked for his support, without revealing who.
A key Leave campaigner in the Brexit referendum, Boris Johnson has said he is prepared to take Britain out of the European Union, "deal or no deal".
In the interview, Mr Trump also repeated his criticism of how Theresa May has handled Brexit negotiations, saying Britain had allowed the EU to "have all the cards".
"It is very hard to play well when one side has all the advantage,
"I had mentioned to Theresa that you have got to build up your ammunition" he said.
Mrs May concluded a divorce agreement with the EU in November but her deal was rejected three times by the British parliament, forcing her to seek a delay in leaving the bloc, now scheduled for 31 October.
Donald Trump is to be received in Buckingham Palace on Monday by Queen Elizabeth II.
He will then have a discussion with Prince Charles, the heir to the British throne, who is known for speaking out against global warming, an issue the US President is dismissive of.
Donald Trump has decided to pull the US out of the Paris climate change agreement that seeks to curb carbon emissions.
A meeting with Meghan Markle, the former US actress who married Charles's second son Prince Harry, is not on the agenda for president Trump, whom she criticised during his 2016 campaign to be America's leader.
"What can I say? I didn't know that she was nasty," Donald Trump said of the Duchess of Sussex, though he also said he was "sure she will do excellently" as a princess.
As for protests that are expected to dog Donald Trump's state visit to the Britian, the president insisted "I think I am really, I hope, I am really loved in the UK".
