Donald Trump and the Queen both gave speeches during a state banquet at Buckingham Palace on Monday night.
Mr Trump raised a toast to the “truly remarkable reign” of Her Majesty, after she praised the “longstanding relationship” between the UK and US.
Anti-Trump protesters had gathered outside the palace to demonstrate ahead of the event, which was boycotted by Labour leader Jeremy Corbyn and other senior political figures.
Mr Trump insisted that he had not seen any evidence of protests, writing on Twitter: “London part of trip is going really well… Tremendous crowds of well wishers and people that love our Country.”
Protesters are set to hit the streets of London in their thousands on the second day of Donald Trump’s state visit as he prepares to hold talks with Theresa May.
The main demonstration against the president’s trip is scheduled for today, with as many as 250,000 activists expected to march from Trafalgar Square to Downing Street.
Labour leader Jeremy Corbyn is gearing up to lead the demonstration, which has been planned to coincide with the US President’s talks with the Prime Minister.
Donald Trump appeared to breach royal protocol by touch the Queen on the back as she stood for his toast at the state banquet to mark his UK visit.
The US President briefly put his left hand behind the monarch and may have touched her gently as she stood following his speech at the event in Buckingham Palace.