Prince William met the leader of the free world after President Joe Biden made a detour to say hello, ahead of his Earthshot Prize awards.
Royal aides only discovered in recent days that the US leader would be in Boston at the same time, and were delighted when the White House said he would like to make time to speak in person.
As the royal already had an engagement at the John F Kennedy Presidential Library and Museum with Caroline Kennedy, JFK’s only surviving child, President Biden even offered to come to him.