Donald Trump and Melania were welcomed by the Queen, the Prince of Wales and Duchess of Cornwall at Buckingham Palace this afternoon.
But the one detail that royal watchers picked up on was the way in which the US President and First Lady greeted the monarch.
The couple did not bow or curtsy to the Queen as most guests would. Instead, Her Majesty offered her hand for a formal handshake.
Mr and Mrs Trump were criticised for failing to display the traditional greeting when they met with the Queen last year, but it isn’t mandatory to bow or curtsy.
The Royal Family’s website says “there are no obligatory codes of behaviour when meeting The Queen” but many people like to observe the traditional forms - a bow for men and a curtsy for women.
Following the welcome, the national anthems of the US and the UK were played, before the president and Prince Charles inspected a Guard of Honour formed by Nijmegen Company, Grenadier Guards.
The president and first lady then attended a private lunch with the Queen, Charles, Camilla, Prince Harry, Prince Andrew, the Duke and Duchess of Gloucester and the Duke of Kent at the palace.
The couple were then shown items from the Royal Collection relating to America.
This evening, the Trumps and the Royal Family will attend a state banquet at Buckingham Palace.