The Duke and Duchess of Cambridge and their children are on Canadian soil. Of course, such a royal occasion requires a proper welcome by Prime Minister Justin Trudeau and his wife, journalist Sophie Grégoire Trudeau.
There's no question the two couples enjoy each other's company.
Prime Minister Justin Trudeau, his wife Sophie Gregoire Trudeau, Prince William and Catherine, Duchess of Cambridge, react while watching children play during a visit to the Immigrant Services Society in Vancouver on September 25, 2016.
They likely have a lot to chat about as Trudeau's youngest son, two-year-old Hadrien, is right between Prince George and Princess Charlotte in age. (However, Hadrien is more free with the high-fives than George.)
Duchess of Cambridge, Prince William, Prime Minister Justin Trudeau and his wife Sophie Gregoire Trudeau during a visit to the Immigrant Services Society in Vancouver.
But that is not all these two families have in common. They go way back, considering Trudeau's father hosted the royals several times when he was prime minister. This included Prince William's parents, Prince Charles and Princess Diana.
Prince Charles travelled to Canada when he was still single in 1975 and 1976. Both times, he was photographed chatting candidly with Trudeau's mom, Margaret.
During this visit, Charles travelled to Ottawa, the Northwest Territories, New Brunswick, Nova Scotia and Montreal.
The Prince of Wales returned to Canada repeatedly on his own in the following years, but in 1983 his wife Princess Diana accompanied him. By this point, Pierre and Margaret were separated.
Trudeau remembers this trip well.
"I was eleven years old and playing on the driveway of 24 Sussex with my friend Jeff Gillin," he recalls in his memoir Common Ground. "A car pulled up, the door opened, and an elegant young woman stepped out carrying a gym bag: it was Diana, Princess of Wales. She and Prince Charles were touring Canada at the time and I had been told she was discreetly coming over to swim some laps in the pool … Jeff, his eyes as large as saucers exclaimed, 'Oh my God! That was incredible!'"
We'd all feel like that, Jeff.