In 2002, she gave up her full-time royal duties and her HRH title to pursue a life away from the spotlight.
She is survived by her husband, Prince Edward, Duke of Kent, and their three children.
Buckingham Palace said in a statement: “It is with deep sorrow that Buckingham Palace announces the death of Her Royal Highness The Duchess of Kent.
“Her Royal Highness passed away peacefully last night at Kensington Palace, surrounded by her family.
It continued: “The King and Queen and all Members of The Royal Family join The Duke of Kent, his children and grandchildren in mourning their loss and remembering fondly The Duchess’s life-long devotion to all the organisations with which she was associated, her passion for music and her empathy for young people.”
Flags on public buildings have been lowered to half-mast.
Her cause of death is yet to be revealed.
Royal engagements are likely to continue, although households will consider the ‘format and tone’ during the period following the death of the 92-year-old.