Queen Camilla will lead the royals in paying tribute to the late King Constantine II, the last king of Greece, at a special memorial service in Windsor.
Buckingham Palace has confirmed that Her Majesty will be joined by members of the royal family at the Thanksgiving Service at St George's Chapel on Tuesday 27 February.
The British royals will also be accompanied by King Constantine's family, including his wife, Queen Anne-Marie, and his eldest son, Crown Prince Pavlos.
The service will be led by the Dean of Windsor, The Right Reverend Dr Christopher Cocksworth, and will be attended by foreign royal families and other guests.
Constantine passed away at the age of 82 on 10 January 2023 after suffering from ill health for a number of years. He was buried privately in the Royal Cemetery at Tatoi, with a number of royals attending his funeral in Athens, including the Princess Royal and her husband, Vice Admiral Sir Tim Laurence.
King Charles, who is currently undergoing cancer treatment, is a second cousin of Constantine through their fathers.
Constantine II, as the only son of King Paul I and Queen Frederica, succeeded his father as King of the Hellenes in 1964. However, he would rule for less than a decade after a military junta abolished the monarchy.
Constantine lived in exile for many years in Hampstead Garden Suburb, before eventually returning to his native country in 2013.
He shared five children with his wife, Queen Anne-Marie (sister to Denmark's Queen Margrethe) – Princess Alexia, Crown Prince Pavlos, Prince Nikolaos, Princess Theodora and Prince Philippos. The King also had two sisters, Queen Sofia of Spain (mother of King Felipe) and Princess Irene.
The Greek's relationship with the British royals remains close to this day. King Charles named Constantine as one of Prince William's godparents and William would later become godfather to Constantine's first grandson, Constantine-Alexios.
Sadly, the King and the Prince of Wales could not attend Constantine's funeral in Athens last year. The monarch and Queen Camilla had a scheduled meeting with the President of the Republic of Cyprus, while William had a "private" engagement that was not recorded on the Court Circular.