Prince William and Prince Harry’s uncle Lord Robert Fellowes died Monday. He was 82.
The cause of death is “undisclosed,” according to his obituary published in the London Times Wednesday.
Fellowes became Princess Diana’s brother-in-law in April 1978 when he married her sister Lady Jane Fellowes.
The late Princess of Wales was one of Jane’s bridesmaids.
The couple went on to welcome daughters Laura, 44, and Eleanor, 38, and son Alexander, 41, all of whom have yet to publicly address their dad’s death.
William, 42, and Harry, 39, also have not released statements on the loss.
Robert worked in banking before and after he served as Queen Elizabeth II’s private secretary from 1990 to 1999.
Notably, he worked for the late monarch during Diana’s 1996 divorce from King Charles III after his affair with now-wife Queen Camilla.
Robert also advised Elizabeth the following year when Diana died in a car crash.
After the accident, Robert called the late princess “a good, good person” in a statement.
“I was deeply fond of her,” he said at the time.
“She found it difficult in life to find happiness, and I’m sad for people who have that situation.”
