The Queen has said she wants Camilla, the Duchess of Cornwall, to be known as Queen Consort when Prince Charles becomes King.
In a message marking the 70th anniversary of her reign, the Queen said it was her “sincere wish” that Camilla would have that title.
There had been suggestions Camilla would be known as Princess Consort.
But the Queen’s announcement paves the way for her to be known as Queen Camilla in the future.
A Clarence House spokesman said the Prince of Wales and Duchess of Cornwall were “touched and honoured”.
The Queen’s message, marking her accession to the throne in 1952, directly addresses the unresolved question of the Duchess of Cornwall’s future title.
“It is my sincere wish that, when that time comes, Camilla will be known as Queen Consort,” she writes.
“Queen Consort” refers to the spouse of a ruling king and would mean “Queen Camilla” as her future title.
There has been a different practice for male consorts of a monarch, such as Prince Philip or Queen Victoria’s husband, Prince Albert, who have become Prince Consort rather than King.
The usual precedent would have been for Camilla to automatically become Queen when Charles was King, but because of uncertainty about public opinion it had been suggested that might not be the case.
Charles and Camilla were both divorcees when they married in 2005 in a civil marriage. Charles had previously been married to Princess Diana but they divorced in 1996, a year before she died in a car crash in Paris.
At the time of their marriage the official intention was for Camilla to be known as the Princess Consort. But plans for her title became more ambiguous in recent years.
The Queen’s intervention means barriers to her becoming Queen have now been removed, and will allow her to have a fully-fledged royal role beside Charles.
The Queen’s personal endorsement follows her New Year announcement that Camilla would become a member of the Order of the Garter – the highest order of chivalry.
Camilla, aged 74, has increasingly been involved in championing her own causes and interests, including charities supporting victims of domestic abuse.