Donald Trump is likely to meet the Queen when he visits the UK this July, the BBC understands.
They will either meet at Buckingham Palace or Windsor Castle, BBC North America editor Jon Sopel said.
The US president is to visit the UK on Friday, 13 July, after previously cancelling a trip amid claims he would face mass protests.
Downing Street called it a "working visit" – not the full-blown state visit Mr Trump was promised last year.
Mr Trump will hold talks with Prime Minister Theresa May, Downing Street said, with further details to be "set out in due course".
Mrs May she was "looking forward to welcoming President Trump to the United Kingdom for a working visit on July 13".
The July date follows the Nato summit in Brussels which the president is expected to attend.
Downing Street and the White House hoped to co-ordinate releasing details of the trip, but Mr Trump's spokeswoman Sarah Sanders apparently let slip the information first.
Mr Trump cancelled a planned trip to London to open the new US embassy in Vauxhall earlier this year, complaining the move to an "off location" south of the Thames had been a "bad deal".
But critics said his decision may have been driven by a fear of protests.
Foreign Secretary Boris Johnson tweeted that it was "fantastic" news Mr Trump was visiting.
Meanwhile his successor as mayor of London, Labour's Sadiq Khan – who clashed with the US president over London terror attacks and Mr Trump's proposed ban on Muslims entering the US – said the president would experience a city that chose "unity over division".
Skip Twitter post by @SadiqKhan
If he comes to London, President Trump will experience an open and diverse city that has always chosen unity over division and hope over fear. He will also no doubt see that Londoners hold their liberal values of freedom of speech very dear.
— Sadiq Khan (@SadiqKhan) April 26, 2018
End of Twitter post by @SadiqKhan
Some have been suggesting that Mr Trump should avoid London, where protests are expected.
More than 33,000 people on Facebook have already said they will attend a protest organised by left-wing journalist Owen Jones.
Six Conservative groups – including the think tanks the Bow Group and the Bruges Group – have written to Mr Trump urging him to focus his visit on his "ancestral home" of Scotland, where his mother was born.
"A visit to London by the president is likely to draw major protests, crime and disorder, and we do not wish to see Britain or President Trump embarrassed by this," Ben Harris-Quinney, chairman of the Bow Group, said.
"Many in Britain… wish for President Trump to be afforded the warmest of welcomes," he added.
"Sadly that will not be the case in London."
But the US ambassador to Britain, Robert Wood Johnson, told LBC radio Mr Trump was "thick-skinned" and would "definitely" be going to London.
Lib Dem leader Sir Vince Cable told the BBC he would be "amazed" if there were not "substantial protests".
Kate Allen, Amnesty International UK's director, said: "When Donald Trump arrives on these shores, we and thousands of our supporters will very definitely be making our voices heard."
Shadow home secretary Diane Abbott said on BBC One's Question Time that she would not join protests, but defended the rights of others to do so – saying Mr Trump's "actions and his attitudes have made him so frightening to so many people in this country".
Theresa May was the first foreign leader to visit Mr Trump in the White House following his inauguration in January 2017.
She conveyed an invitation from the Queen for Mr Trump to come for a state visit – a formal occasion with much pomp and ceremony.
Mr Trump accepted the invitation but a date has yet to be set, amid speculation it has been postponed indefinitely.
Plans for a working visit to the UK in 2018 were announced when Mr Trump met Mrs May at the World Economic Forum in Davos in January.