The Queen and the Duke of Edinburgh are celebrating their 65th wedding anniversary.
They are spending the day together privately at their London home Buckingham Palace after an evening out at the Royal Variety Performance on Monday night.
The Queen is the first British monarch to reach a 65th wedding anniversary.
Although the couple's schedule is free of public engagements, the Queen has audiences in the morning with the outgoing and incoming Commanding Officer of the 3rd Battalion The Royal Welsh and the High Commissioner for Belize.
Their Blue Sapphire anniversary falls in the same year that the monarch marked her historic Diamond Jubilee.
Philip, 91, was forced to miss some of the key celebrations during the special bank holiday weekend honouring the Queen's 60-year reign after falling ill with a bladder infection. He was taken to hospital the day after braving cold, wet and windy conditions on the royal barge for several hours during the Diamond Jubilee Pageant on the River Thames.
The Duke was also taken to hospital in August for a recurrence of the bladder infection during his summer break in Balmoral in Scotland and previously had a successful procedure to clear a blocked coronary artery last December, spending four nights in hospital over Christmas.
Princess Elizabeth and Prince Philip of Greece first met in 1934 when they attended the wedding of Philip's cousin, Princess Marina of Greece to Princess Elizabeth's uncle, the Duke of Kent.
The Princess and Lieutenant Philip Mountbatten, who became a naturalised British subject and changed his surname, married on November 20 1947 at Westminster Abbey, where the the Duke and Duchess of Cambridge wed last year. The ceremony provided the nation with a morale boost in the austere post-war days amid the widespread rationing facing the country.
They honeymooned at Broadlands, Hampshire - the home of Philip's uncle Lord Mountbatten - and also at Birkhall on the Balmoral estate.