Ambassador Johnson sought to play down Trump's comments.
But, he added: "Whether he sees it, whether he reacts to it, we don't really care".
The exterior of The Trump Arms public house, formally named The Jameson, which has embraced the arrival of US President Donald Trump for a visit by changing its name and decorating its interior with Trump memorabilia, is seen in West London on July 12, 2018.
During his news conference on Thursday, the USA president also appeared to refer to Ireland as part of the United Kingdom.
Melania's Friday morning plans will differ greatly from her husband's, since she will be meeting members of the public; something Trump will not be doing during his time in the United Kingdom.
Trump "has proudly sparked passionate often divisive emotions about things, I think Americans living here to eager to turn out and express their views", he said.
Trump's trip is part of a working visit and not a state visit, an invitation to which was extended to him personally by May just days after his inauguration.
Protests are expected against Trump, whose policies - including a travel ban on a number of predominantly Muslim countries, the detention of child migrants on the US-Mexico border and the imposition of tariffs on European Union steel and aluminium exports - have all been criticised by the UK.
"We need to show the world what millions of people in this country think of the bigotry and the hatred that he represents", protest organizer Owen Jones said.
Nick Hurd, Britain's Policing Minister, told parliament police expected more than 100 protests across the country, including two large demonstrations in London on Friday, and there were robust and proportionate plans in place.
Trump will spend Thursday night in London at Winfield House, the official residence of U.S. Ambassador to Britain Robert "Woody" Johnson.
"Give us your tired and your oppressed and we'll divide you from your children", he said mockingly of Mr. Trump's policies. Separately, his wife, Melania, will visit war veterans and schoolchildren in a London visit accompanied by Philip May, the prime minister's husband.
"The people voted to break it up, so I imagine that's what they'll do".
President Donald Trump will get the red-carpet treatment on his brief visit to Britain beginning today: military bands at a gala dinner, lunch with the prime minister at her country residence and tea with the queen at Windsor Castle before flying off to one of his golf clubs in Scotland.
Ignoring all diplomatic niceties, the convention-shredding U.S. president set up the four-day visit with a rebuke of his beleaguered host as she battles to stop her government falling apart over Brexit.
Trump was making his first trip to Great Britain as president after a tense summit with North Atlantic Treaty Organisation leaders in Brussels that began Wednesday and on the heels of ruptures in May's government because of the crisis over Britain's exit from the European Union.