On Monday, President Biden and King Charles had their first formal meeting at Windsor Castle.
Ahead of the meeting, eagle-eyed online commentators were quick to point out that Biden may have broken royal protocol by casually placing his hand on the monarch's back while outside Windsor Castle and walking in front on him for the inspection of the Guards of Honor.
A Buckingham Palace source told ET that King Charles was "entirely comfortable" with United States' President Biden touching the monarch's back. "What a wonderful symbol of warmth and affection it was between both the individuals and their nations," the source added.
The source said that despite claims of breaking protocol -- it was actually keeping with the correct protocol that the president walked in front of the king during the inspection of the Guard of Honor.
On Monday, the monarch and the U.S. president had a briefing on the Climate Finance Mobilisation Forum and ways they could encourage businesses in their respective countries to enact climate saving-initiatives and practices.
However, before their meeting, King Charles met President Biden outside the castle where they shook hands and walked together up to a platform where a live band played both countries' national anthems and they inspected the famed Welsh Guards.
It was during this exchange that Biden placed his hand on King Charles' back.
Biden and King Charles have met several times in the past. In 2011, King Charles and Queen Camilla traveled to meet with then-President Barack Obama in the Oval Office at the White House, where then-Vice President Biden was present.
In 2021, both Biden and King Charles attended the COP26 United Nations Climate Change Conference. And in September 2022, the Bidens attended Queen Elizabeth II's funeral service.
The formal meeting between King Charles and President Biden comes two months into the monarch's reign after his coronation in May. Though Biden was not in attendance, his wife, first lady Jill Biden, was present in the Westminster Abbey church service audience.