Princess Diana would be “very angry” and “very sad” about the way he and his wife have been treated, her son Prince Harry said.
In his explosive interview with Oprah Winfrey, the UK's Duke of Sussex also suggested that other members of the royal family were jealous of the Duchess of Sussex, his wife Meghan Markle, and her popularity on her first official overseas trip in 2018.
Buckingham Palace has remained silent since the interview was first broadcast more than 24 hours ago.
Addressing his decision to step down as a senior working royal, Prince Harry said his mother would ultimately approve, suggesting his relocation to California was only possible because of the inheritance Princess Diana left him after she died 23 years ago.
Prince Harry said "it's like she saw it coming", after he claimed he was "cut off financially" by the royals, after his decision to leave.
“I have what my mum left me, and without that we wouldn’t have been able to do this,” he told Ms Winfrey.
“It’s like she saw it coming and she’s been with us through this whole process.”
In one of the more damaging claims in the interview, the prince said that his father and heir to the throne, Prince Charles, stopped taking his calls when he wanted to step back from royal duties.
Prince Harry said he felt "really let down" by his father.
"There's a lot to work through there, you know?” he said. “I will always love him but there’s a lot of hurt that’s happened."
He added that Charles and his older brother William were "trapped" by the conventions of the monarchy.
Asked how Princess Diana would feel about his exit from royal life, Prince Harry said: "I think she would feel very angry with how this has panned out and very sad, but ultimately, all she'd ever wanted is for us to be happy.”
Prince Harry compared his wife's treatment to that of his late mother.
“I can't begin to imagine what it must've been like for [my mother] going through this process by herself all those years ago," he said.
He claimed everything “really changed” after the couple’s tour of the South Pacific in 2018, in which they completed 76 engagements in Australia, New Zealand, Tonga and Fiji.
Ms Winfrey asked whether the trip could be compared with Prince Charles's 1983 trip to Australia with Princess Diana. In an episode of drama series The Crown, Charles is portrayed as jealous of the attention received by his wife on the trip.
Ms Winfrey said: “Are you saying there were hints of jealousy?”
The duke replied: “Look, I just wish that we would all learn from the past. But to see … how effortless it was for Meghan to come into the family so quickly in Australia and across New Zealand, Fiji and Tonga, and just be able to connect with people.”
Royal biographer Andrew Morton, who wrote Diana: Her True Story in 1992, said the Winfrey interview would "shudder down through the generations in the same way that Diana's did", referring to the princess's controversial Panorama interview in 1995.
“We are having a re-run of so many things, that Harry’s concerned about Meghan, that she would suffer the same fate as his mother,” he said.
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