For their historic meeting, both the Queen and Jackie Kennedy donned shades of blue, posing with their husbands in the drawing room of the palace.

Between 1938 and 1940, Joseph Kennedy Sr. served and the U.S. Ambassador to the UK. Naturally, that involved attending quite a few political events with royalty—like this one that Kennedy and his wife, Rose, were seen at alongside King George VI and then-Queen Elizabeth in May 1939.

Joe Sr. and Rose also attended a banquet marking the Fourth of July with Prince George, the Duke of Kent, the younger brother of King George VI that same year.

Of course, Joe Sr.'s ambassadorship was only the beginning of the Kennedy political dynasty's connection with the royal family. Twenty years later, his son, John F. Kennedy, would become the first U.S. President to dine at Buckingham Palace since 1918 when he and his wife Jackie Kennedy were hosted by Queen Elizabeth II and Prince Philip in June 1961.

While rumors that the Queen and First Lady didn't get along abounded, according to Jackie's secret service agent at the time, Clint Hill, "They had a good relationship. I know that the press has sometimes written it otherwise, but that's not really true. The relationship was friendly, more warm than it was cold."

"May I also at the same time say how grateful my wife and I are for the cordial hospitality offered to us by your Majesty and Prince Philip during our visit to London last Monday," JFK wrote to Queen Elizabeth following their historic dinner. "We shall always cherish the memory of that delightful evening."

The following year, Jackie was hosted at Buckingham Palace by the Queen once again, this time for a luncheon. While no photos were taken at the private meetup, Jackie was seen leaving the home of her sister Lee Radziwill in London on her way to the palace.

Following the 1963 assassination of JFK, the British government established a memorial to the late president in Runnymede, England. Queen Elizabeth inaugurated the memorial in May 1965 with Jackie Kennedy and her children, Caroline and John Jr.

JFK Jr., who was only four at the time, bowed politely to the Queen.

“The unprecedented intensity of that wave of grief, mixed with something akin to despair, which swept over our people at the news of President Kennedy’s assassination, was a measure of the extent to which we recognized what he had already accomplished, and of the high hopes that rode with him in a future that was not to be," Queen Elizabeth said at the dedication.

Along with Jackie, Caroline, and John Jr., JFK's brothers Bobby and Ted also attended the service.

As the royal family and the Kennedys shared a moment in front of the newly inaugurated memorial, JFK Jr. held hands with his mother and Prince Philip.

During his November 2005 tour of America, then-Prince Charles met with Maria Shriver, whose mother, Eunice, was the sister of JFK. At the time, Shriver was the wife of the governor of California, Arnold Schwarzenegger, and introduced the royal to a gardening initiative in Berkeley, California.

During the trip, Shriver also met with the future Queen Camilla, who joined Charles for their first official foreign tour as a married couple, following their May 2005 wedding.

During their trip to Boston to celebrate the Earthshot Prize—Prince William's initiative to inspire climate change solutions—William and Kate, Princess of Wales, met with Caroline Kennedy, the daughter of JFK and current US Ambassador to Australia, at a Celtics game.

William and Caroline Kennedy met again as the Prince of Wales paid a visit to the John F. Kennedy Presidential Library and Museum. Kennedy is the honorary president of The John F. Kennedy Library Foundation, which is a host partner for the Earthshot Prize ceremony.