Of course, in 2009, during a Buckingham Palace reception before the G20 summit, Michelle sparked headlines by embracing the British royal - putting her arm around her as they chatted.
The Trumps were greeted with traditional pomp and circumstance when they arrived at Windsor, with the queen's guards marching and playing the U.S. national anthem.
One suspects that the Queen hasn't planned anything else for the day of the President of the United States' first visit to Britain, although she might be anxious that the 3-15 at Kempton is about to start without her.
Once the Trumps arrived they were greeted with a smile from the queen, so whether she was upset about the wait-time or not, she hid it.
Trump made a MAJOR faux pas.
One person wrote on Twitter: "How are you not gonna bow to the Queen?".
Melania Trump wore a pale pink fitted Dior suit for the occasion.
"My wife is a tremendous fan of hers. I would-I would actually say she probably went the opposite way".
On Friday afternoon, May and Trump were together at a joint press conference after holding previously scheduled talks at the prime minister's country residence Chequers. He also took aim again at Khan, saying: "I think allowing millions and millions of people to come into Europe is very, very sad". You don't see, like, anything embarrassing. A soft Brexit could require the United Kingdom to comply with certain regulations from the European Union, which would likely benefit large corporations, but not small businesses, she said.
"CNN is fake news", he said.
Mr Trump told reporters: "He's been very nice to me".
Queen Elizabeth II, who is now 92, has sat on the throne for 66 years.