Crown Prince Pavlos paid tribute to his late father, King Constantine II, on the first anniversary of his passing on Wednesday.
The head of the Greek royal family shared a poignant photograph of the last King of the Hellenes on his Instagram account.
The snap showed a carefree Constantine at the helm of a boat, with the view of the sea and the mountains behind him and the Greek flag flying in the wind.
Crown Prince Pavlos, 56, did not caption the image but his followers flooded the comments section with heartfelt messages of support.
The Greek royal family are expected to attend a private memorial service in Tatoi on Wednesday afternoon, where Constantine is laid to rest next to his parents, King Paul and Queen Frederica.
According to Andreas Megos, a memorial service will take place in London on 27 January "in the presence of King Charles, friends and associates of the late King from abroad". Buckingham Palace is yet to confirm the King's attendance.
Constantine II was a second cousin of King Charles through their fathers, and the British and Greek royals have maintained a close relationship. Charles even named Constantine as one of Prince William's godparents and William would later become godfather to Constantine's first grandson, Constantine-Alexios.
The King and the Prince of Wales received criticism for not attending Constantine's funeral in Athens last January. The Princess Royal represented Charles, while another one of Constantine's godchildren, Lady Gabriella Kingston, attended on behalf of William.
Charles and William's absences were justified by Buckingham Palace and Kensington Palace at the time. The monarch and Queen Camilla had a scheduled meeting with the President of the Republic of Cyprus, and the Prince of Wales had a "private" engagement that was not recorded on the Court Circular.
Constantine passed away at the age of 82 on 10 January 2023 after suffering from ill health for a number of years.
He acceded to the Greek throne in 1964 following the death of his father, King Paul. 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 2010.
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.
Pavlos and his wife, Crown Princess Marie-Chantal, divide their time between New York, London and Greece. The couple have five children – Princess Maria-Olympia, Prince Constantine-Alexios, Prince Achileas-Andreas, Prince Odysseus-Kimon and Prince Aristidis-Stavros.