The Late Queen's dresser and right hand woman is said to have been caught up in a row with other Palace staffers.
Angela Kelly is said to have became so close to the late Queen, she was part of a small team of loyal courtiers locked down with her and Prince Philip and the Queen at Windsor Castle.
Kelly was the former monarch's personal dresser and designed many of her most memorable and colourful outfits and was often pictured in public with the Queen.
However, on one occasion, sources say a row broke out which caused the Queen's top aide to storm off.
According to sources, on the night of the Queen's 94th birthday, she allowed the staff to have champagne with their supper.
And while members of the team suggested standing for a toast, while others felt it was unnecessary and could be done sitting down given the intimate gathering.
The growing tension reportedly led to Kelly storming from the room, the MailOnline reports.
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Angela Kelly also reportedly game to blows with Prince Harry, following an incident in which he said he hoped is grandmother was surrounded by the "right people" - which sources claim she interpreted as a dig at her.
Tensions also reportedly dated back to 2018 during a rift over what tiara Meghan Markle would wear to her wedding.
Meghan was given the option to choose between five diamond and gem-encrusted tiaras and after making her decision had asked whether she could practice wearing it before the big day.
However, Harry wrote in his memoir Spare that Kelly did not respond to their messages to get access to the chosen tiara.
He writes: "She was being obstructive. But for what reason we couldn't even hazard a guess.”
The Duke of Sussex later boldly writes: "To my mind, Angela was a troublemaker, and I didn't need her as an enemy."
Recent reports claim Kelly has fallen out of grace and favour with the Royals, and took to Instagram to say she would be leaving a property on the Windsor estate.
She also seemed to confirm that her work phone had been disconnected and that she would be moving north closer to her family.
It comes amid reports after the Queen's death last September she was facing an uncertain future with King Charles, said to be not a fan of hers, now in charge.
Kelly posted a picture of what appeared to be her garden.
Accompanying the snap, she wrote: "Getting ready to say goodbye. I am moving at last to my new home which I will be able to call My Home at last."
