Trump and the 92-year-old monarch shared a few interactions on Friday as they reviewed troops at the royal castle in Windsor.
Thousands began protesting in London as British Prime Minister Theresa May welcomed US President Donald Trump to her official country residence for a meeting that is expected to be unusually tense, after he trashed her Brexit plan in a newspaper interview.
He also spent time at Chequers, the prime minister's country residence, where he sought to heal wounds inflicted by an explosive newspaper interview in which he had said Mrs May's Brexit plans would kill any trade deal with the USA and that Boris Johnson would be a "great prime minister".
Apparently Trump has been wanting to meet with Queen Elizabeth for a while. You don't see, like, anything embarrassing.
His four-day trip to Britain is not a state visit - with the formal trappings of a carriage procession and certain banquets - but it bears numerous hallmarks, including time with the head of state.
The Trumps were greeted with traditional pomp and circumstance when they arrived at Windsor, with the queen's guards marching and playing the USA national anthem.
Though he retracted these comments today and showered praise on Mrs May and the "great job" she was doing with negotiations.
The President, now changed into a red and blue striped tie, and Melania climbed out of the auto and, after handshakes and a little small talk, they stood either side of the monarch, towering over her, as the United States national anthem was played.
Other protestors waited outside Windsor Castle for the president to arrive. Oh dear, she just looked at her watch.
Trump has previously spoken about Prince William's wife Kate and his late mother Diana.
The US president questioned her handling of Brexit in an interview with The Sun tabloid, published on Thursday.
He added that former foreign secretary Boris Johnson would make a "great prime minister", saying "I think he's got what it takes".
But it is unlikely the Trumps even saw them.