Sarah Ferguson Says She and Princess Diana Would Have a 'Granny-Off': 'She Would Run Faster in the Races'

Sarah Ferguson knows Princess Diana would have made a wonderful grandmother.

Sarah, whose title is Duchess of York (and who is popularly known as Fergie), appeared on Good Morning America on Tuesday and remembered Diana, who died in a Paris car crash in 1997. She said that Princess Diana would be "very proud" of her five grandchildren from her sons, Prince William and Prince Harry.

"I think we'd have a 'Granny-Off,' " the Duchess, who is a grandmother to Princess Beatrice and Princess Eugenie's children, quipped. "Because she would run faster in the races. I wonder — she'd probably be funnier. No, I think I'd be funnier."

Sarah, 63, said in an exclusive interview with PEOPLE that her grandchildren "just follow me around like Peter Pan. I'm 'Super Gran Pan!' "

Princess Beatrice is a mother to 1-year-old daughter Sienna Elizabeth and is a stepmother to husband Edoardo Mapelli Mozzi's son Wolfie from a previous relationship, while Princess Eugenie welcomed son August in Feb. 2021 and is currently expecting her second child with husband Jack Brooksbank.

Ferguson added that her grandchildren "think I'm very funny" — and they are always expanding her world.

"August is teaching me about trains. My girls had Barbie dolls," she noted.

Fergie added that Prince William, 40, and Prince Harry, 38, are "really special boys."

"What I'm thrilled about is seeing Harry so happy," she said of Harry's life with his wife Meghan Markle and their two children, 3-year-old son Archie Harrison and 1-year-old daughter Lilibet Diana. "He's got his lovely wife, and he's got beautiful children. He deserves to be loved like that."

In an exclusive interview with PEOPLE, Sarah touched on how the Duke and Duchess of Sussex are creating their own path after leaving their royal roles and moving to California.

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"I don't believe that any single person has the right to judge another person. I'm not in a position myself to make any judgments," says the Duchess of York, whose new novel, A Most Intriguing Lady, is out March 7. "I have been judged all my life, and I have no judgment on the Sussexes."