King Charles and the Prince of Wales are set to attend a significant joint engagement this week at a major ceremonial event. The father and son will both take part in the elaborate traditions of the Order of the Bath service on Friday.

For Prince William, this will mark his first time participating, as he will be formally installed as Great Master of the historic order during a ceremony at Westminster Abbey.

King Charles, who served in that role for nearly five decades, passed it on to his eldest son last year on St George’s Day, in a series of notable appointments that also included honours for the Queen and the Princess of Wales.

This year’s event holds added significance as it marks the 300th anniversary of the order, which recognises exceptional service in the military or civil sectors.

It will also be the King’s first time taking part in the ceremony as the sovereign of the order. Both Charles and William will wear traditional crimson satin robes as they take part in the procession through the Abbey, accompanied by officers, knights, and the Dame Grand Cross, before taking their places in the Quire.

Despite continuing cancer treatment, the King is expected to appear alongside William, just weeks after Prince Harry’s television interview in which he claimed his father had stopped communicating with him and that he was unsure how long the King had left.

Charles and William will later proceed to the Abbey’s Lady Chapel of King Henry VII for the formal installation. There, the Prince of Wales will take an oath as Great Master, followed by the induction of five new Knights Grand Cross. The ceremony includes a traditional offering of gold and silver by the sovereign at the altar. The newly installed knights will then present their own offerings and place their swords on the altar.

Founded by King George I in 1725, the Most Honourable Order of the Bath is believed to have roots dating back to the 8th century. Its name comes from the symbolic ritual of bathing, which was originally part of the spiritual purification required before knighthood. Candidates once had to undergo practices such as fasting, prayer, and vigils in preparation for their honour.

During Queen Elizabeth II’s reign, it became customary to bestow honorary Grand Cross titles upon visiting heads of state. One of the most well-known recipients was former US president Ronald Reagan.

The service is traditionally held every four years, with the Great Master present each time and the monarch attending every eight years. In April of last year, King Charles appointed the Princess of Wales as the first Royal Companion in the history of the Order of the Companions of Honour, recognising her contributions to public life and the arts.

At the same time, Queen Camilla was named Grand Master and First or Principal Dame Grand Cross of the Most Excellent Order of the British Empire.