In the early years of their marriages, Princess Diana and Sarah Ferguson had a close bond.
The pair had known each other since they were teenagers and grew even closer when they both married their princes and joined the royal family.
They were often pictured chatting at events, such as Ascot, and took their children on skiing holidays together with Fergie frequently describing Diana as her best friend.
But it's thought that in 1996 the pair's relationship became strained and at the time of Diana's tragic death a year later, they were not on speaking terms.
Their fall-out was covered in Fergie's second tell-all memoir, Finding Sarah.
In it, she wrote: "Diana was one of the quickest wits I knew; nobody made me laugh like she did.
"We took vacations together with our children. Sadly, at the end [of the Princess’s life] we hadn't spoken for a year, although I never knew the reason, except that once Diana got something in her head it stuck there for a while."
However, according to the Daily Mail, the reason stemmed back to Sarah's previous autobiography called My Story.
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Before it was released, Diana is reported to have told her former sister-in-law not to include any gossip about her in it.
But Sarah included an unflattering anecdote, saying she got a verruca after wearing a pair of shoes she borrowed from Diana - causing the rift.
Recently, Sarah has been talking once again about her friendship with Diana saying how the late princess would have been so proud of her sons, Princes William and Harry, and how she would have split her time between the UK and California.
She also said that Diana would have been proud of her son's wives and would have been "obsessed" with her grandchildren - Prince George, Princess Charlotte, Prince Louis, Archie and Lilibet.
And speaking to Bella magazine, Sarah says that if Diana were still alive, they would have been "party grannies" together.
She said: "Diana and I had the same complete love for children. We both loved nothing more than to put a smile on a child’s face
"We’d be having granny parties together and having a great time. I wonder whether there would be room for the kids to get onto the bouncy castle, as she and I would be the first on."
