King Charles is set to give a historic address to Congress in which he will say that while the UK and the US have not always agreed on everything, they have “always found ways to come together”.
He and Queen Camilla are set to meet with US President Donald Trump and first lady Melania Trump at the White House on Tuesday.
Charles is expected to use his speech to promote unity between the two countries at a time of marked differences between their two governments, with the Iran war causing recent transatlantic strains.
This is Charles’ first visit to the US as monarch and the first state visit of any British monarch since 2007.
The King and Queen are celebrating the 250th anniversary of American independence, which kicked off with a massive garden party at the British Embassy in Washington yesterday.
Tuesday’s address will be only the second of its kind in history. The first and only British monarch to address Congress was Charles’ mother, Queen Elizabeth II, in 1991 during the George H W Bush administration.
The state visit is under heightened security after Saturday’s shooting at the White House Correspondents’ Association dinner.