A Guard of Honour, formed of the Coldstream Guards, gave a Royal Salute and the US national anthem was played as the US visitors arrived for the engagement. Mr Trump is the 12th president to meet Her Majesty.
The Queen and President Trump inspected the Guard of Honour before watching the military march past. Mr and Mrs Trump will then take tea with the Queen in the castle.
The Queen looked elegant in a periwinkle blue coat and matching hat for the occasion while Mrs Trump changed out of the £1,550 striped Victoria Beckham dress she wore earlier today and into a cream skirt suit for the meeting.
Mr Trump hailed the Queen as a ‘tremendous woman’ in his interview with the Sun today.
He told the paper: ‘If you think of it, for so many years she has represented her country, she has really never made a mistake. You don’t see, like, anything embarrassing. She is just an incredible woman. My wife is a tremendous fan of hers. She has got a great and beautiful grace about her.’
President Trump and the First Lady arrived at Windsor Castle by Marine 1, landing on the eastern lawn – out of view of protesters who had gathered outside one of the castle gates.