After intensive talks at Chequers in the wake of an interview in which he said the Prime Minister's Brexit plans would kill off a trade deal with America, the U.S. president told Mrs May "whatever you do is OK with me" but urged her to "make sure we can trade together".
In the incendiary interview, with the Sun newspaper, the United States leader criticised Mrs May's handling of Brexit negotiations, hailed Boris Johnson - who quit the cabinet earlier this week - as a future and "great Prime Minister" and said there was too much immigration in Europe.
The US president said the former foreign secretary, who resigned on Monday in protest at the Prime Minister's Brexit plan, had been "very nice to me".
Trump also said that immigrants were destroying European culture and that he planned to maintain good relations with Russian President Vladimir Putin despite nerve agent attacks on United Kingdom soil that have been blamed on the Kremlin.
"I must say, I've gotten to know Theresa May much better over the last two days than I've known her over the previous year and a half..."
"So I think allowing millions and millions of people to come into Europe is very, very sad", he said.
He said the stunt aims to "hold up a mirror" to Mr Trump's "toddler-like politics". Before meeting the queen, he called her an "incredible woman" and said he was excited to meet with her. "Whatever you do is OK with us, just make sure we can trade together, that's all that matters".
After the question was posed to the U.S. president, the reporter appeared to be ushered out of the room at Chequers, the official residence of the PM.
In the interview, Trump said that Theresa May had ignored his advice on Brexit. But even before he arrived, the president criticized May's Brexit plan, said the country was in "somewhat turmoil" and that meeting with Russian President Vladimir Putin next week - the British premier's geopolitical enemy - would be easier than meeting with her. I have a lot of respect for her.
Mr Trump used the interview with the Sun to lay into Mr Khan, who criticised the American leader as "ill-informed" over a tweet following the London Bridge attack in June 2017. "We should cherish the fact they've got the right".
More than 64,000 people signed up to demonstrate in London against the visit and other protests were expected in major cities around the country. "I haven't been there in a long time". "I said, 'I want to apologize because I said such good things about you, ' And she said, 'Don't worry, it's only the press'".