Lord Robert Fellowes, Prince William and Prince Harry’s uncle by marriage, has passed away at age 82.

Lord Fellowes was married to the late Princess Diana’s sister Lady Jane Fellowes and served for a time as the late Queen Elizabeth II’s private secretary. He d_ied of undisclosed causes on July 29.

Plans for the British courtier’s funeral have not yet been revealed.

Lord Fellowes had a firm place within the royal fold, and was considered one of the late monarch’s most trusted advisers during his tenure between 1990 and 1999.

During that time, Fellowes advised the late Queen on the divorces of three of her children, as well as on Diana’s passing in 1997.

Lord Fellowes was married to Lady Jane Fellowes for 46 years, until he di..ed.

The late Princess of Wales served as a bridesmaid at the couple’s lavish wedding in 1978.

The couple went on to welcome three children: Alexander Robert, 41, Eleanor Ruth, 38, and Laura Jane, 44, who is Princess Charlotte’s godmother.

In 1986, He rose up the ranks at Buckingham Palace to become deputy private secretary, before taking over the reins from Sir William Heseltine as private secretary four years later.

Fellowes left his post as private secretary to the Queen in February 1999 and returned to his previous position in the private sector, as a banker.

That year, he received the title of Baron Fellowes of Shotesham in the County of Norfolk in the Queen’s Birthday Honors List.

He sat as a Crossbench Peer — a member of Parliament not belonging to a political party — until his retirement in 2022.

Though he left his role as private secretary, Fellowes remained technically a member of the royal household.

He remained an extra equerry to the late Queen until she di,,ed in September 2022 at age 96.

Extra equerries are honorary appointees who are rarely required to serve, but can be called upon to do so if needed by senior members of the Firm.

Fellowes was proud of a close friendship with Harry and William, attending the Prince and Princess of Wales’ wedding at Westminster Abbey in 2011.

He continued to be close to both of the now-estranged brothers, and attended the Duke and Duchess of Sussex’s wedding at Windsor Castle in 2018.

Fellowes was portrayed in the hit Netflix series “The Crown.” He was played by actor Andrew Havill.