Queen Elizabeth II on Sunday became the first British monarch to reign for seven decades, expressing her "sincere wish" for Camilla, the wife of her heir Prince Charles, to ultimately be known as Queen Consort.
Elizabeth II made the announcement in a message renewing her pledge to spend her life serving the nation as she began her Platinum Jubilee in subdued fashion at Sandringham, her estate in eastern England.
Britain's longest-serving monarch acceded to the throne aged 25 on February 6, 1952, following the death of her father King George VI.
In a major statement on the future of the royal family, the 95-year-old expressed her "sincere wish that, when that time comes, Camilla will be known as Queen Consort".
Charles warmly praised Camilla in a message marking the Jubilee, saying: "my darling wife has been my own steadfast support throughout", adding that they were "deeply conscious of the honour represented by my mother's wish".
He paid tribute to the Queen's "devotion to the welfare of all her people (which) inspires still greater admiration with each passing year".
The Queen said she hoped that when Charles, now 73, becomes monarch, the British people would give him and Camilla, now 74, "the same support that you have given me".
Charles and Camilla, now known as the Duke and Duchess of Cornwall, had a highly publicised adulterous relationship and Camilla was vilified for her role in the break-up of Charles' marriage to Princess Diana.
When the couple married in 2005, the royal family announced that Camilla would become known as Princess Consort due to the sensitivity of the issue, but she has gradually won plaudits as the future king's loyal wife.
The Queen's suggestion means Camilla would be crowned alongside Charles and be known to the public as Queen Camilla, The Sunday Telegraph wrote.
'Historic reign'
With the main Platinum Jubilee celebrations set for this summer, the Queen said she hoped the events would "bring together families and friends, neighbours and communities".
Prime Minister Boris Johnson said he looks forward to the summer "when we will be able to come together as a country to celebrate her historic reign".
He also praised the Queen's "inspirational sense of duty and unwavering dedication".
German Chancellor Olaf Scholz in a tribute said the Queen's reign "has been unique and an inspiration to people around the world".
Four days of festivities are planned for early June, coinciding with the anniversary of her 1953 coronation, including a military parade and music concert, street parties, a nationwide "Big Jubilee Lunch" and a "Platinum Pudding Competition".
On Monday, there will be ceremonial gun salutes marking Accession Day in London's Green Park, close to Buckingham Palace, and at Edinburgh Castle in Scotland.
During her reign, the Queen has remained a constant through periods of huge social and political upheaval - a living link to Britain's post-war and imperial past.
In her message addressed to the public signed "Your servant, Elizabeth R", the Queen said she wanted "to express my thanks to you all for your support".
She also renewed a pledge she first gave in a broadcast on her 21st birthday "that my life will always be devoted to your service".
In September 2015, she surpassed Queen Victoria's 63 years and seven months on the throne and, despite some health concerns over the past year, her latest message shows she is determined to continue her record-breaking reign.
After husband Philip's death in April last year, the Queen returned to public and official engagements, including hosting world leaders at the G7 summit.
She was forced to slow down on advice from doctors, however, after an overnight hospital stay in October sparked public concern.
Since then, she has largely stayed at Windsor Castle and made few public appearances.
But on Saturday, the Queen held a reception for locals at Sandringham, reportedly her largest in-person public engagement since the autumn health scare.