The U.S. president's state visit may not see major progress on the big issues of the day, but it's guaranteed to make headlines nevertheless.
Then, following the terrorist attack on London Bridge and Borough market in 2017, the President accused Mr Khan of "pathetic" behaviour.
The two politicians have clashed publicly since 2016, when Mr Khan, a Muslim, called Mr Trump a "buffoon" for calling for a "shutdown" on Muslims entering the US.
The scientists are concerned that President Trump has taken a series of decisions that apparently undermine efforts to reduce emissions of carbon dioxide and other greenhouse gases in the USA and internationally.
Mr Trump said it was a "mistake" not to have involved Mr Farage in talks with the European Union, adding that the Brexit Party leader had a "lot to offer".
The situation in Iran will also be discussed during the state visit.
Draymond Green wants National Basketball Association to let Drake keep doing his thing
Golden State was able to hold on and win that game before closing out the series with an impressive Game 6 performance in Houston. Not a Raptors game, at least one with the global ambassador in attendance, goes by without Drake making his presence known.
"I would walk away".
"So we will be going to the United Kingdom, I think it will be very important, it certainly will be very interesting, there's lot going on in the United Kingdom, and I am sure it is going to work out very well for them", Trump told reporters before departing.
"The prime minister can robustly challenge President Trump about his inaction on climate change with the knowledge that she has the extremely strong support of all the experts who signed the letter", Mr Ward commented.
The meal, held in the Ballroom at the Palace, will include the showpiece speeches of the State Visit with both the Queen and President Trump making addresses. "I think he would be excellent", Trump said.
Meanwhile, at least 250,000 people are expected to protest in central London on Tuesday morning, on a route between Trafalgar Square and Parliament Square, when Trump meets May in Downing Street.
After all, the primary goal of the visit is to honour the last surviving D-Day veterans - and all those soldiers who gave their lives in the Second World War so Britain, America and their allies in a liberated Europe and beyond could shine brightly as beacons of freedom and liberty.
He will also take part in commemorations to mark the 75th anniversary of the D-Day landings.
Trump told the Sunday Times in an interview that Britain should "walk away" from talks and refuse to pay a 39-billion pound ($49 billion) divorce bill if it doesn't get better terms from the EU.