For years rumors have persisted that Princess Diana and Sarah "Fergie" Ferguson had a fallout before the royal’s tragic death – but the Duchess of York said they had an unshakable bond until the end.

"We promised each other we would always be together – there was never any daylight between us," the 61-year-old told People magazine on Wednesday. "But everybody wanted that because we were so strong together. People want to break something so strong."

Diana and Ferguson first met as teenagers before they married two of Queen Elizabeth II’s sons.

"We were best friends from when she was 14 and I was 15," she told the outlet, noting that her nickname for Diana was "Duch."

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"She taught me so much of public life," Ferguson reflected. "She was so brave. We used to have the most incredible time together."

Princess Diana and the Duchess of York were childhood friends before they married Prince Charles and Prince Andrew.

Princess Diana and the Duchess of York were childhood friends before they married Prince Charles and Prince Andrew. (Photo by Tim Graham Photo Library via Getty Images)

Ferguson was married to Prince Andrew from 1986 until 1996. They share two daughters: Princess Beatrice, 32, and Princess Eugenie, 31.

"[Diana] adored my girls," Ferguson told the outlet. "She adored [her] boys. This would be her haven. Her heaven."

"She would be very proud of her sons and their wives," Ferguson continued. "And she would be just like me, obsessed with her grandchildren. Because that’s what she loved… If she were sitting with me right now, I know she would say, ‘I am so proud of both of my boys and the wonderful wives they have chosen. Because each has got her own voice."

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Diana was married to Prince Charles, the queen’s eldest, from 1981 until 1996. The princess passed away in 1997 from injuries she sustained in a Paris car crash. She was 36.

Britain's Prince William, Duke of Cambridge (L) and Britain's Prince Harry, Duke of Sussex unveil a statue of their mother, Princess Diana at The Sunken Garden in Kensington Palace, London on July 1, 2021, which would have been her 60th birthday. 

Britain's Prince William, Duke of Cambridge (L) and Britain's Prince Harry, Duke of Sussex unveil a statue of their mother, Princess Diana at The Sunken Garden in Kensington Palace, London on July 1, 2021, which would have been her 60th birthday.  (Photo by DOMINIC LIPINSKI/POOL/AFP via Getty Images)

On July 1, which would have been her 60th birthday, Diana’s sons Prince William and Prince Harry unveiled a statue of their late mother in the Sunken Garden at London’s Kensington Palace, a place she once found solace.

The statue, which shows a larger-than-life Diana surrounded by three children, was commissioned by the brothers in 2017. The style of her dress is meant to evoke the final period of her life. It was a time when she gained confidence in her humanitarian work.

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"Today, on what would have been our mother’s 60th birthday, we remember her love, strength and character – qualities that made her a force for good around the world, changing countless lives for the better," William, 39, and Harry, 36, said in a joint statement. "Every day, we wish she were still with us, and our hope is that this statue will be seen forever as a symbol of her life and her legacy."

The Associated Press contributed to this report.