(CNN) — Prince William will miss the memorial service for the late King Constantine of Greece due to a personal matter, a royal source told CNN.
The Prince of Wales, 41, was expected to attend a memorial service at Windsor Castle on Tuesday.
The source did not elaborate on the last-minute change of plans, but said William's wife, the Princess of Wales, who is recovering from stomach surgery in January, “continues to do well”.
The same source added that William called the family and informed them that he would not be able to attend.
Kate has stayed out of the public eye as she continues to recuperate at home and is not expected to return to royal duties until after Easter.
King Charles III is also out of service as he continues treatment for an undisclosed cancer. Many of the messages of support the 75-year-old monarch has received since she was recently diagnosed with cancer have reduced her to tears.
Another royal source told CNN that the Prince of Wales' personal matter had nothing to do with the monarch's health.
Queen Camilla leads the family in a gathering to commemorate the last Greek monarch at St George's Church.
Constantine II of Greece, a second cousin of King Charles III, died in January last year aged 82.
Charles and Constantine enjoyed a close relationship, and the British royal family named his cousin godfather to their first-born son, William.
After a military coup in 1967, Constantine and his family fled to Rome and the junta appointed a regent in his place.
The Greek monarchy was abolished on June 1, 1973, when the military junta declared the country a republic, which was supported by a subsequent referendum. Constantine accepted the abolition in 1974 after the elected civilian government held another referendum.
