Of course these days the two politicians have nothing for praise for each other – and last night the US president praised the Tory leadership hopeful, saying he’s “been very nice”.
Trump added: “Well, I think I may meet with him. He’s been a friend of mine... I have a very good relationship with him.”
But it wasn’t always this way.
In 2015, Johnson was scathing in his condemnation of the then-presidential candidate and it was these comments that graced Big Ben last night.
In the clip, Johnson says: “Donald Trump’s ill-informed comments are complete and utter nonsense. I think he’s betraying a quite stupefying ignorance that makes him frankly unfit to hold the office of President of the United States.
“I think Donald Trump is clearly out of his mind if he thinks that’s a sensible way to proceed, to ban people going to the United States in that way, or to any country.
“I would invite him to come and see the whole of London and take him round the city but I don’t want to expose Londoners to the risk to any unnecessary risk of meeting Donald Trump.”
Later on Monday, Led By Donkeys revealed they has also projected Trump’s popularity rating in the UK onto the Tower of London, alongside Barack Obama’s far more flattering figure.
Trump landed in the UK shortly after 9am on Monday and had already caused great offence even before the wheels of Air Force One had touched the ground at Stansted, targeting London Mayor Sadiq Khan in a series of tweets.
He wrote: “Sadiq Khan, who by all accounts has done a terrible job as Mayor of London, has been foolishly “nasty” to the visiting President of the United States, by far the most important ally of the United Kingdom.
“He is a stone cold loser who should focus on crime in London, not me......”
He added: “Kahn reminds me very much of our very dumb and incompetent Mayor of NYC, de Blasio, who has also done a terrible job - only half his height.
“In any event, I look forward to being a great friend to the United Kingdom, and am looking very much forward to my visit. Landing now!”
Earlier, as he left the White House, the US president said he expected his three-day state visit to be “very important” and “very interesting”.
Monday’s itinerary includes a ceremonial welcome at Buckingham Palace at noon followed by a visit to the Royal Collection and then an event at Westminster Abbey.
In the afternoon, the presidential couple will have tea with the Prince of Wales and Duchess of Cornwall, followed by a state banquet.