On Tuesday, October 29, Sophie joined her Majesty in hosting a reception at Buckingham Palace to celebrate the work of the Queen Elizabeth Diamond Jubilee Trust to prevent unnecessary blindness.
At the event, the Countess - who is married to the Queen's youngest son, Prince Edward - gave a touching speech about the Queen's lifelong work to improve the Commonwealth.
However, other members of the royal family have different nicknames for the monarch.
"George is only 2 ½, and he calls her ‘Gan-Gan,’" the Duchess of Cambridge said at the time.
Prince Philip is rumoured to have several nicknames for his wife.
The Netflix drama The Crown reveals that the Duke of Edinburgh refers to the Queen as "Lilibet" and "sausage."
Her Majesty is also affectionately known as "Cabbage," to Prince Philip which derives from the French term "mon petit chou," which means "my darling".
"I was told on very good authority that that is what the duke sometimes calls the Queen," the screenwriter of the 2006 film The Queen, Peter Morgan told The Times.
The film includes Philip telling his wife to "move over, cabbage" as he is about to get in bed.