Trump's royal encounter is not a state visit - an offer that was extended to him by Prime Minister Theresa May in the early days of his presidency.
The president and first lady Melania Trump were delivered by chauffeured Range Rover this morning to the courtyard of Windsor Castle, where Queen Elizabeth II was awaiting them under a canopy on a dais - far from the anti-Trump protesters demonstrating across London.
The British Guard of Honor, wearing formal military attire of red coats with fluffy bearskin hats, saluted the Trumps and played the "Star-Spangled Banner" as the Trumps flanked the Queen.
While it's unknown whether the Trumps were late to their first meeting with the queen, Twitter couldn't help but continue to point out her actions. As the world's longest reigning monarch, crowned in 1952, she has already met 10 US presidents.
"The Star-Spangled Banner" was then played and the Queen guided the president on a review of the honour guard in the castle courtyard. The President wore a suit and tie and the first lady wore a pale pink suit with a skirt and black belt.
The Queen escaped any extended hand-holding, faced in the past by world leaders such as the Prime Minister and French President Emmanuel Macron.
Trump appeared to avoid any gaffes in his introduction to the Queen this afternoon.
Queen Elizabeth's tea for the Trumps was due to last 25 minutes according to the White House's schedule, the last part of their official visit.
"He did literally eclipse her, but I don't think that was deliberate".
The former Celebrity Apprentice host said: "If you think of it, for so many years she has represented her country, she has never really made a mistake".
"You could see that suppressed dominance where he felt that he had to still motion to her. Then to add insult to injury he keeps the Queen waiting 15 mins, doesn't bow just shakes her", tweeted Melanie Cassandra Burstall.
"My mother loved the queen".
Trump said his respect for the queen is hereditary.