"I would say Brexit is Brexit, the people wanted to break it up so I would imagine this is what they will do".
On terrorism: After coming under fire for re-tweeting anti-Muslim videos posted online by the deputy leader of the far-right Britain First group, Jayda Fransen, the president said Theresa May should focus on "destructive radical Islamic terrorism" in the United Kingdom, rather than on him.
Trump has always been a supporter of Brexit and has expressed enthusiasm for a wide-ranging trade deal with Britain after it leaves the European Union, something heralded by Brexit supporters as being one of the great benefits of exiting the bloc.
May is trying to unify her deeply divided Conservative Party behind her Brexit plans with some of her own lawmakers openly speaking of a leadership challenge.
She said: "There is no stronger alliance than that of our special relationship with the USA and there will be no alliance more important in the years ahead".
However, despite the welcome from May, many Britons remain deeply opposed to Trump's visit.
The US president is set to touch down for his visit on Thursday after sparking a new firestorm on the worldwide stage.
More recently, in February, Trump once again tried but failed to make hand-to-hand contact with his wife as they departed the White House for a trip to Ohio.
Ambassador Johnson's sentiment has been echoed by a number of residents in the north of England, who say that whether they agree with the president or not, he is worthy of respect as America's leader. "I'm very strong on immigration".
As well as in London, protests are expected to take place in Bristol, Newcastle, Leeds, Cambridge and Cardiff after Trump arrives here on Thursday.
Downing Street insisted Mrs May welcomed Mr Trump's decision to "engage" with the Russian leader in the Finnish capital on Monday.
"From the public, the welcome will be far from warm", he told lawmakers on Wednesday, noting there would be protests across the country against Trump's "abysmal record on human rights, his repugnant attitude toward women and his disgusting treatment of minorities".
Meanwhile, in the capital city thousands will gather in a various of protests to voice their views against the United States president, including a march that could be attended by as many as 50,000 people and a flying protest involving the "Baby Trump" balloon.
A campaign is also underway to get "American Idiot", a 2004 song by the USA punk rock band Green Day, to the top of the UK Singles Chart.
One of the demonstrations will begin on the evening of July 12, at Blenheim Palace, Oxfordshire, the birthplace of Winston Churchill. The dinner will include 100 ministers and guests, including people from a variety of sectors.
The two leaders are also expected to discuss Russia, Brexit and Middle East.
She will then head to Windsor Castle for tea with Queen Elizabeth II in the afternoon.
Trump and his wife, First Lady Melania, will land at London's Stanstead airport after attending a North Atlantic Treaty Organisation summit in Brussels.