At what is likely to be the last Commonwealth summit she will attend, the Queen has said for the first time that she wants Prince Charles to take over as its next Head.
At the opening ceremony at Buckingham Palace, where the leaders of the 53 member countries had gathered, the Queen said her son should follow her and lead the organisation which her father, King George VI, founded after the end of the British Empire.
She said: "It is my sincere wish that the Commonwealth will continue to offer stability and continuity for future generations, and will decide that one day The Prince of Wales should carry on the important work started by my father in 1949."
The issue has been an elephant in the room for many years because the position will only become vacant when the Queen abdicates (which she won't) or dies.
It's always been considered distasteful to debate the matter.
But while the issue was swept under the carpet, there were growing calls that the Head of the Commonwealth job should go to someone other than a member of the British Monarchy.
And while the Queen is widely respected across the member states, which span from Canada to the Caribbean and from Africa to Asia, there wasn't thought to be the same affection for the Prince of Wales.
Prince Charles has spent a lot of time in the Commonwealth throughout his life.
His connections began when he was just 5 years old in Malta.
He returned just last week from a tour of Australia and the Pacific state of Vanuatu.
In his speech, the Prince said: "For my part, the Commonwealth has been a fundamental feature of my life for as long as I can remember, beginning with my first visit to Malta when I was just five years old.
It would be a huge blow for the Prince of Wales, who has been heir to the throne since 1952, if the Commonwealth were to reject him.
Theresa May did not refer to the matter when she welcomed the delegates, but her spokesman did say that a decision was due to be made at the end of the summit on Friday.