US President Donald Trump will visit the UK in July - on Friday the 13th.
The long-awaited and controversial trip is expected to be a "working visit" rather than a full-blown state occasion.
The UK's ambassador to the United States confirmed the visit, which will include face-to-face talks with Theresa May.
Downing Street and the White House had hoped to co-ordinate releasing details of the trip, but Mr Trump's spokeswoman Sarah Sanders apparently let slip the information first.
UK ambassador Kim Darroch confirmed the date on Twitter, saying he was "delighted" that Mr Trump would visit the UK.
The British Prime Minister's spokesman said: "The President of the United States will visit the UK on 13 July.
"He will hold bilateral talks with the Prime Minister during his visit. Further details will be set out in due course."
Mr Trump's visit is likely to attract major protests, and even his supporters have urged him to stay away from London in an effort to avoid mass demonstrations.
In a letter to the US President, six UK conservative groups recommend he should instead focus his visit on his "ancestral home" of Scotland, including a meeting with the British Queen at Balmoral.
The Bow Group in partnership with @UKGOP @tfa4freedom@BrugesGroup@ParlStreet @Think_Scotland have written to @realDonaldTrump advising that he has many supporters in the UK, but London is not the best city in Britain for his visit
Don't give the left the chance to embarrass us pic.twitter.com/LGDP8f9R1Q— Bow Group (@bowgroup) April 26, 2018
Plans for a working visit to the UK in 2018 were announced when Mr Trump met Mrs May at Davos in January.
The July 13 date follows the Nato summit which the president is due to attend in Brussels on the previous days.
Interest in Mr Trump's plans has been fuelled by this week's high-profile state visit to the US of Emmanuel Macron, which some commentators have framed as a bid by the French president to make Paris Washington's first port of call in Europe following Brexit.
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 it is thought his decision may have been driven by a fear of protests in the capital, with whose mayor Sadiq Khan he has clashed over his response to terrorism.
The expectation of demonstrations is also believed to have played a part in the postponement of a state visit mooted for 2017.
That trip - which would involve lavish ceremonies and a stay with the Queen at Buckingham Palace - has been put off indefinitely, though Number 10 insists the invitation stands.