Sarah Ferguson has spoken of her heartbreak that "best friend" Diana wasn't alive to see Princess Eugenie get married last month.
The Duchess of York, 59, says the late princess is always at the forefront of her mind. "I thought of absent friends and family; of Diana - but she's with me all the time," she told the Daily Mail.
"What I miss most is her tinkling laughter."
Fergie and Diana knew each other long before they married into The Firm. The pair were distantly related and their parents went to school together.
They helped each other adapt to life in the public eye when they moved into formal roles after their marriages - Diana to Prince Charles, and Fergie to Prince Andrew.
Fergie continued: "Diana was my best friend and the funniest person I knew. She had such timing and wit.
"It was a total joy to be with her because we just laughed and enjoyed life so much, and I know she would have loved the wedding."
Princess Eugenie, Fergie's youngest daughter, married James Brooksbank on October 12 at Windsor Castle - the same chapel Prince Harry and Meghan Markle wed in May.
Fergie spoke about her closeness to Diana in her 1996 autobiography, published just one year before the death of the people's princess.
She wrote: "She was two years younger than I, and I strove to support and protect her as I would a younger sister - as I still do today, as a best friend."
In the tell-all interview, Fergie also broke her silence on rumours of remarriage to ex husband Prince Andrew.
The Duchess of York described the pair as the "happiest divorced couple in the world" after their high-profile split in 1996.
The couple remain on good terms and continue to live together at Royal Lodge in Windsor Great Park.
It has long been rumoured that Prince Philip is the only thing standing between them remarrying.
But Fergie told The Daily Mail that they are happy how they are, adding: "We're divorced to each other, not from each other."
She says the pair are "completely compatible", calling Andrew "the best man" she knows.
This story originally appeared on The Sun and was reproduced with permission.