Now, the two leaders will face the uncomfortable questions stemming from that interview, which emerged while Trump was still at a gala dinner May threw in honor of his visit.
The remarks were in stark contrast to Mr Trump's comments in The Sun on Thursday, which were published as Mrs May entertained him at a lavish banquet.
While he added that he thought Johnson would one day be a good candidate to lead the country, he insisted that he wasn't trying to put Johnson against May.
And he went out of his way to talk up one of her main rivals, Boris Johnson, who resigned earlier this week as foreign secretary.
The blimp is part of a series of protests across the United Kingdom organized by the Stop Trump Coalition, which describes itself as a "coalition of organizations and individuals joined forces to protest against Donald Trump's planned visit to the UK".
"I was very saddened to see he was leaving government and I hope he goes back in at some point".
In another blow to May, Trump said her now ex-foreign secretary "would be a great prime minister".
He said he had gotten to know her a lot better in the last few days and reckoned she was a "tough negotiator and a very smart and determined person" who would do very well. You have a mayor who has done a awful job in London.
He said Sadiq Khan had shown the U.S. disrespect by personally attacking him, while acknowledging that he did not feel welcome in the capital.
Britain's Brexit Secretary Abruptly Quits, Throwing Deal To Leave EU In Doubt
Her spokesman said they discussed the publication of a white paper policy document on Britain's future ties with the EU. The EU says it will respond once it has seen the details. "We want to bring the negotiating process forward", she said.
Trump also reignited his feud with London mayor Sadiq Khan, who has repeatedly blamed for terrorism and personally blamed for immigration into the capital, despite the mayor having no control over immigration policy.
He didn't elaborate. He said that May is "doing a terrific job".
Ahead of his arrival, she said: "When we leave the European Union we will begin to chart a new course for Britain in the world and our global alliances will be stronger than ever".
But for many British diplomats, Brexit marks the collapse of a 70-year British strategy of trying to balance European integration with a USA alliance based on blood, trade and intelligence sharing. He is planning to meet with Russian President Vladimir Putin next week.
Farage, a member of European Parliament and former leader of the U.K. Independence Party, said Trump chose to "intervene" for two reasons: he believes in Brexit and he feels the US has been let down.
But Jacob Rees-Mogg told the Wall Street Journal the comments "cut through" the government's line on the Brexit deal.
A trade deal with the United States is supposed to be the big prize of Brexit, with its potential to largely compensate the economic loss that would ensue by exiting the European single market.
"I think he has done a bad job on crime, if you look, all of the disgusting things going on there, with all of the crime that is being brought in", he said.
He also referenced immigration into Europe, saying: "I think what has happened to Europe is a shame".