Prince Philip, the 96-year-old husband of Britain's Queen Elizabeth, will make his final solo appearance at an official engagement on Wednesday before he retires from active public life.
Philip will attend a parade of Royal Marines at Buckingham Palace after more than 22,000 solo appearances over the last 65 years. He is the Captain General of the Royal Marines.
Philip married Elizabeth at Westminster Abbey in 1947, and the couple are due to celebrate their platinum, or 70th, wedding anniversary in November.
Buckingham Palace has said that Philip, who is also known as the Duke of Edinburgh, may choose to accompany Elizabeth at certain events in the future.
Elizabeth has described Philip as her "strength and stay" during her reign, despite his reputation for stray comments and headline grabbing gaffes.
The queen, the world's longest-reigning living monarch who celebrated her 91st birthday in April, will continue to carry out a full program of official engagements.