US President Joe Biden inspected the guard of honour alongside Britain’s King Charles III, after arriving on Monday at Windsor Castle.
It was Biden’s first meeting with the British monarch since he was crowned in May. They discussed climate change and ways of mobilising private companies to do more to bolster clean energy in developing countries.
The US leader also held Ukraine-focused talks in London with UK Prime Minister Rishi Sunak. Both men are attending this week's NATO summit in the Lithuanian capital, Vilnius.