Donald Trump is expected to meet the Queen when he makes his long-awaited visit to the UK on Friday July 13, according to reports.
The US president has been warned to expect protests during the controversial trip, which will be a "working visit" rather than a full-blown state occasion.
One element of contention is whether he will meet the Queen, an occasion usually associated with state visits.
Full details of the trip are yet to be announced although various media reports have said Mr Trump will meet the Queen, with the suggested location either Buckingham Palace, Windsor Castle or Balmoral.
Meanwhile the visit will provide Theresa May with an opportunity to highlight the importance of the "special relationship" between the UK and US - and push for the prize of a trade deal after Brexit.
But the outspoken and unpredictable president will face mass protests from critics of his policies and behaviour.
In a sign of the difficulties in dealing with the Trump White House, No.10 had hoped to co-ordinate releasing details of the trip, but the president's press secretary Sarah Sanders slipped out the information first during a "take your child to work day" event.
The prime minister said: "I am looking forward to welcoming President Trump to the United Kingdom for a working visit on July 13."
Downing Street said further details of the visit will be set out "in due course".