Trump has referred to May as "my Maggie", a reference to the strong Cold War relationship in the 1980s between then-British prime minister Margaret Thatcher and United States president Ronald Reagan.
The schedule referred to the prime minister three times as "Teresa May", leaving out the "h" in her first name. Teresa May is also the name of a British former soft porn actress and model.
The President said he was "honoured" by May's visit and that relations between the two long-standing allies had never been stronger as the leaders held a press conference at the White House. The mistake was rectified half an hour after the email was sent out on Thursday.
To make matters worse, it took them 30 minutes to correct the mistake, before the Office of the Press Secretary issued a second memo marked "updated" with the corrected spelling of her name.
Mrs May announced that the Queen has invited Mr Trump for a state visit to the United Kingdom - and also signalled he had reassured her about America's commitment to North Atlantic Treaty Organisation and pledged to continue the working relationship between the two countries.
Other bets include the possibility of Trump giving May a gift - showering her with gold (25/1) - and the announcement that Britain will pledge funding for the Mexican wall (40/1).
And to do that she is relying on the so-called "special relationship" - a term coined by then-prime minister Winston Churchill in a 1946 speech - between the U.S. and UK.
But despite becoming the UK's second female PM, the porn star stole her thunder on social media.
Her name began trending on Twitter after Andrea Leadsom pulled out the race to become the next Conservative party leader.
She was followed across the pond by a plane-load of journalists from the UK. "The 2nd scene is the best, but the last scene (bondage scenario) is amateurish at best".