Author Claims Prince Andrew's 'Nasty' Remarks About Kate Middleton Sparked Feud with Prince William

Prince Andrew's strained relationship with Prince William may have deeper roots than royal protocol — with a new book claiming it began over alleged remarks about Kate Middleton.

Prince Andrew's alleged "nasty" comments about Kate Middleton were a key trigger in his ongoing rift with his nephew, Prince William, according to royal biographer Andrew Lownie.

The Duke of York, 65, has reportedly been distant from both William and Prince Harry for years, with recent reports suggesting the Prince of Wales, 43, considers his uncle a "problem."

In his new book "Entitled: The Rise and Fall of the House of York," Lownie claims Andrew made "rude" and "unkind" remarks about the Princess of Wales. The author suggests these alleged comments stemmed from jealousy, as Andrew was envious of Catherine's rising importance within the royal family following the death of Queen Elizabeth II.

"I can't see how anyone could make unkind comments about Kate when she's been the family's saving grace," Lownie told Radar Online.

"It surprised me, but people do get jealous," he continued. "I'd have thought Prince Andrew would respect William as future king though."

While the specific remarks have not been revealed, Lownie suggests they were enough to prompt William to distance himself from his scandal-hit uncle. The biographer also noted that William's frustration with Andrew has grown in recent years.

According to insiders, Andrew's future within the monarchy has effectively been decided — he is not expected to return as a working royal under William's reign. Both William and Kate reportedly view him as a risk to the Firm, given his past ties to convicted sex offender Jeffrey Epstein and alleged Chinese spy Yang Tengbo.