Lady Diana Farnham - who served as the Queen's lady of the bedchamber for 34 years - died at age 90 on December 29, and her death has left the Queen feeling "very sad".
A royal source told the Daily Telegraph newspaper: "Everyone loved Lady Farnham, she was always so good-humoured. She was also a very glamorous and attractive woman."
Lady Farnham rode alongside the Queen on the way to the Diamond Jubilee service in 2012, and she was considered to be a major figure in the royal household.
The insider added: "She was always very generous to new people joining the household."
Lady Farnham's death came just weeks after Ann Fortune FitzRoy, the Duchess of Grafton, - another of the Queen's ladies-in-waiting - died on December 3.