As a trusted aide to the late Queen, Lady Susan Hussey was at the monarch's side for more than 60 years as a lady-in-waiting.
And even after Her Majesty died just under three months ago, she was kept on in the role as a lady of the household.
But today she has resigned and apologised after allegedly asking a black visitor at Buckingham Palace: "What part of Africa are you from?"
In a Twitter post, Ngozi Fulani, who runs a black women's domestic abuse charity, claims she was questioned about her ethnicity by Lady Susan.
An investigation has been launched and the palace slammed the "unacceptable and deeply regrettable comments".
Queen's 'number one head girl'
Lady Susan was a long-standing lady-in-waiting after joining the Royal Household in 1960 to help answer correspondence.
She is the youngest daughter of the 12th Earl and Countess of Waldegrave and was married to BBC Chairman of the Board of Governors, Marmaduke Hussey, from 1959 until his death in 2006.
Already Dame Commander of the Royal Victorian Order, she was promoted to Dame Grand Cross of the Royal Victorian Order in 2013.
She is said to be a friend of King Charles and is one of Prince William's six godparents.
According to Tatler, she quickly became known in the office as ‘Number One Head Girl’ and stayed in her position as 'Woman of the Bedchamber' until the late monarch's death just under three months ago.
As a lady-in-waiting, she accompanied the Queen in the car as she arrived at the funeral of her beloved husband Prince Philip last April. It is believed the Queen personally asked Lady Susan, 83, to sit with her as she travelled to St George's Chapel.
In September she was seen attending the Queen's funeral along with her fellow former ladies-in-waiting.
Meghan comment
In a recent book, it claims that Lady Susan warned that Prince Harry and Meghan Markle 's marriage would "all end in tears".
She is said to have made the comment a few months before the couple wed at a lunch with a group of theatre executives.
The comments were revealed in a book about Meghan called Revenge: Meghan, Harry And The War Between The Windsors, by Tom Bower.
He writes in the book: "While discussing the possibility that Meghan might become linked with the National Theatre after the wedding, Hussey became unexpectedly serious about the couple’s future.
"'That will all end in tears,' she is alleged to have warned. 'Mark my words.'"
The book also claims that Lady Susan visited Meghan at Nottingham Cottage - the property in the grounds of Kensington Palace where she lived with Harry - to offer advice and help when she joined the Royal Family.
New position
Following the death of the late Queen, new Queen Consort Camilla has decided not to appoint traditional ladies-in-waiting.
However, Lady Susan along with fellow former ladies-in-waiting Mary Morrison and Dame Annabel Whitehead were confirmed to be known as as ladies of the household.
They were appointed to assist the King in hosting formal occasions at Buckingham Palace, as they had done recently.
However, just days after his announcement, Lady Susan has now resigned and apologised after she made "unacceptable and deeply regrettable comments" at a reception at the palace yesterday when she allegedly asked charity boss Ngozi at Buckingham Palace: "What part of Africa are you from?".
A palace spokesman said: "We take this incident extremely seriously and have investigated immediately to establish the full details. In this instance, unacceptable and deeply regrettable comments have been made. We have reached out to Ngozi Fulani on this matter, and are inviting her to discuss all elements of her experience in person if she wishes.
"In the meantime, the individual concerned would like to express her profound apologies for the hurt caused and has stepped aside from her honorary role with immediate effect.
"All members of the Household are being reminded of the diversity and inclusivity policies which they are required to uphold at all times."
