King Juan Carlos of Spain has been installed as an Extra Knight of the Garter, a Christian brotherhood more than 600 years old.
Juan Carlos, 51, joined the ancient order of chivalry in a pageant at Windsor Castle this week.
Twenty-five knights of the order, many of them elderly, made their annual procession to the installation service.
Queen Elizabeth II made Juan Carlos an Extra Knight Companion during her visit to Spain last October.
Because he was handed the insignia of the order at the time, the king had to forgo the ceremony for new knights when the queen buckles the blue and gold garters on their left leg to symbolize Christian brotherhood.
Juan Carlos, who joins the sovereigns of Norway, Belgium, Denmark, Holland, Luxembourg and Sweden as Extra Knights Companion, walked in the procession with the Queen Mother. They followed Prince Charles and the Duke of Kent and preceded the queen and her husband, Prince Philip.