The royal author released his highly-anticipated book Endgame on Tuesday, which included several negative statements about members of the Royal Family.
One such statement was about the Duchess of Edinburgh, 58, who married the King's youngest brother Prince Edward in 1999.
Scobie referenced a Telegraph interview that the Duke and Duchess of Edinburgh gave following Meghan Markle and Prince Harry's sit-down with Oprah Winfrey in 2021.
WATCH NOW: Omid Scobie defends his explosive new book, Endgame
According to the author, Sophie said, regarding Winfrey: “You know, if you’re not into chat shows, there’s no reason why you should know who she is. Certainly not in this country, anyway.”
Scobie responded by calling the Duchess of Edinburgh "casually bigoted".
He explained: "Whether it was a 'joke' (as a source close to the couple later claimed it was) or not, the comments about the world’s most successful Black woman and one of the biggest faces in entertainment made them seem stuffy or tin-eared at best, and casually bigoted at worst."
Gareth Russell, a royal author and biographer of the late Queen Mother, spoke exclusively to GB News to explain how Sophie would have responded to these "bridge-burning" comments.
Duchess of Edinburgh is known to be a hardworking royal
He said: “I think the book is an exercise in bridge-burning.
"Intentionally or, as looks tentatively likely, unintentionally, the Sussexes look like they’ve set fire to nearly every relationship within the Royal Family.
"Sweeping judgements, like describing the Duchess of Edinburgh as 'casually bigoted,' is a new tactic and I would imagine quite upsetting for Sophie.
"But while it’s early days yet, the book does not seem to have been created by a tidal wave of credulity.
Omid Scobie has previously written a book about Prince Harry and Meghan MarkleITV
Meghan Markle sat down for an Oprah Winfrey interview in 2021Reuters
"Readers, thus far, seem to be dubious about some of its claims.
"I think many people feel sceptical that Omid Scobie could have written a book with so many details without having received some of them via the Sussexes.
"Or, as we now know happened with his first book about them, through aides sent to talk to him on the Duchess’s behalf, with notes and briefs prepared beforehand by her for the topics of conversation.”