Historian Robert Lacey authored ‘Battle of Brothers’ which is being published later this month. The book focuses on the declining bond between Prince William and Prince Harry.
According to Mr Lacey Meghan Markle, who Harry began dating in 2016, clashed with elements of the royal establishment.
Speaking to the Sunday Times he said: “There was personal animosity in the palace towards Meghan — and the feeling is mutual.
“There was somebody in the palace — and I can’t name them — who hated Meghan.
“There is no love lost there.”
Harry and Meghan announced their engagement in November 2017 after 15 months of dating.
The couple were married in May 2018 at Windsor Castle’s St George’s Chapel.
One year later Meghan gave birth to their first child, Archie Mountbatten-Windsor.
According to Mr Lacey Harry’s relationship with Meghan, a divorced American actress, caused surprise in royal circles.
After a brief stay in Canada they settled in California, Meghan’s home state.
Recently the Duke and Duchess brought a new home to the north of Los Angeles.
The luxurious property comes complete with a tennis court, swimming pool and children’s cottage.
Mr Lacey argued there was a cultural clash between Meghan and some other members of the Royal Family.
He said: “The problem with the Royal Family is that it doesn’t know how to do ‘woke’.
“Woke is not going to go away.
“It’s here to stay, and Meghan is the very embodiment of it.”
Separately a Republican Congressman wrote to the British Ambassador accusing Harry and Meghan of “interference” in the upcoming presidential election.
Mr Jason Smith claimed Meghan’s views are “thinly disguised and widely reported”.
The Duchess recently branded the upcoming poll “the most important election in our lifetime” and urged Americans to register to vote.