When is the Queen of Belgium not the Queen of Belgium? Answer: when she is not correctly addressed as Queen of the Belgians.
In a case of better late than never, Hong Kong officials have admitted they made a royal error during Queen Mathilde's three-day visit earlier this month.
In official press releases before and during her tour, the Hong Kong government referred to her as the Queen of Belgium.
But this title "simply does not exist", said Paul De Vos, the Belgian deputy consul general in Hong Kong.
The correct title is Queen of the Belgians, and the same goes for the king, who is known as King of the Belgians.
"The title goes back to the founding of the country in 1831 when Belgium pioneered the first constitutional monarchy," De Vos said.
It means that the king and queen are not absolute monarchs, and were leaders of the inhabitants, not the country.
"It is not an insult but it is simply wrong," he said.
In his 30 years as a diplomat, De Vos could not recall a government making such a correction, but said the error was "perfectly understandable".
He added: "We appreciate the government's steps to realise the mistake and to correct it."
A spokeswoman for the Hong Kong government's protocol division said: "We approached the Consulate General of Belgium for clarification and were told that overseas media sometimes refer to Queen Mathilde as 'Queen of Belgium'.
"The Consulate General does not mind the department addressing the Queen as such.
"Considering that it is an official visit by the Queen, the Information Services Department decided that it would be more appropriate to use the Queen's official title in its press releases."