The trio watched as the Coldstream Guards marched past the dais in ideal formation and the military band played before they entered the Sovereign's Entrance of Windsor Castle for tea precisely 10 minutes after their arrival.
Half-shaded by a tent, the queen stood in a blue hat and coat in blazing sunshine waiting for the president and first lady Melania Trump to arrive. Hours later, in a press conference with May, and after having a better time that he'd initially expected, Trump backed down on harsh comments and then outright denied making them. In 1982 President Reagan and Mrs Reagan visited the Castle.
There were handshakes all around, and then the threesome stood side-by-side as a military band played the American national anthem.
After Mr Trump's arrival, the pair inspected the Guard of Honour before watching Coldstream Guards unit march past.
The controversial 45th President of the United States will visit the UK for the first time in his position on Thursday, July 12. She also met Harry Truman in 1951 when she was still a princess.
The visit to Windsor Castle by President Trump, who is a known fan of the British Royal Family and has spoken in the past about his mother's love for the British Royals, is clearly one he has looked forward to. The protests come one day after Trump referenced the unflattering balloon during an explosive interview with British tabloid publication The Sun, saying how Londoners make him feel "unwelcome".
"I actually told Theresa May how to do it, but she didn't listen to me", he said.
"You could see that suppressed dominance where he felt that he had to still motion to her". Perhaps she wanted to be early, or just wanted a good first look at the Cold Stream military band that performed the US national anthem for the trio once they all arrived.
Trump even characterized USA -U.K. ties as a "special relationship" - that is, "the highest level of special" - after spending time with May over the past couple days.
U.S. President Donald Trump with Queen Elizabeth II, inspects the Guard of Honour at Windsor Castle in Windsor, England.