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 Sir Kim Darroch confirmed the date on Twitter, saying he was "delighted" that Mr Trump would visit the UK.
The 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 conservative groups recommend he should instead focus his visit on his "ancestral home" of Scotland, including a meeting with the Queen at Balmoral.
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.
The letter to Mr Trump was signed by the heads of conservative thinktanks the Bow Group, Bruges Group, Parliament Street and the Freedom Association, as well as the chairman of Republicans Overseas Scotland and a contributor to ThinkScotland.
They told the president the political and media establishment in London was "far out of touch" with the feelings of ordinary people outside the capital, many of whom "strongly support" his leadership.
"Your ancestral homeland of Scotland represents a powerful bond between you and Britain, and given the nature of the climate in London, it is a superior destination," they said.
"As you know, the Royal Estate of Balmoral Castle sits in Scotland's Cairgorms National Park, thus allowing you to make a full state visit as the guest of the Her Majesty the Queen.
"Scotland and the North of England also offer a variety of locations where you would be able to speak directly to ordinary British people and witness the true level of support that exists for you and the special relationship between the US and the UK."
Ben Harris-Quinney, chairman of the Bow Group, said: "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.
"It is important that the people of the United States and its government know there are many in Britain who strongly support the president and the special relationship, and wish for President Trump to be afforded the warmest of welcomes.
"Sadly that will not be the case in London."
Mr Trump, whose mother was born on the Isle of Lewis, made frequent visits to Scotland before becoming president.
His last trip came during the presidential campaign in June 2016, when he visited his golf resorts.