Kate Middleton was privately worried that Meghan Markle "appeared embarrassed" of some of her family members as she prepared to marry Prince Harry, a royal author claims.
The Duchess of Cambridge also "could not understand" why Harry had never met his future father-in-law Thomas Markle Snr before the wedding in May 2018, claims biographer Ingrid Seward.
Prince William, Kate and Harry were once very close, and when former Suits actress Meghan joined The Firm the two couples were hailed as the "Fab Four", but a rift soon divided them.
Ms Seward claims Kate was worried about Meghan's relationship with her family, especially her estranged father, after Harry guest-edited BBC Radio 4's Today programme in December 2017.
Harry told listeners his loved ones were "like the family she (Meghan) never had".
His comment upset members of Meghan's family, including her half-sister Samantha Markle, who has been brutally critical of the American duchess.
For Kate, then pregnant with her third child, Prince Louis, it was "all a bit worrying", Ms Seward claims.
The author told the Sun: "She could not understand why Harry had never met his future father-in-law, nor why Meghan, who Harry assured was 'the one' and 'ticked all his boxes', appeared embarrassed about her family and unwilling to speak about them apart from her mother."
She also claimed: "Both William and Kate wanted to like Meghan if for no other reason than Harry was so madly in love.
"But the women had little in common beyond some polite chatter and their shared interest in tennis."
Meghan's mum Doria Ragland, who lives in Los Angeles, was the only member of the family to attend the wedding at St George's Chapel, Windsor Castle.
Her dad was caught staging paparazzi photos days before the wedding and did not attend, claiming he had suffered heart problems.
Prince Charles walked his daughter-in-law down the aisle instead.
Since that moment, Harry's relationship with members of his family has deteriorated.
During the bombshell interview with Oprah Winfrey, he said there was "space" between him and William and his father had stopped taking his calls for a time after the Sussexes left the UK for Canada in late 2019.
Harry and Meghan now live in Montecito, a Los Angeles suburb, with their son Archie, who turns two next week.
Meghan is pregnant with a baby girl and is due to give birth this summer.
Harry flew back alone for his grandfather Prince Philip's funeral and reunited with his grandmother the Queen, dad Charles and brother William for the first time in a year.
Kate, who this week celebrated her 10th wedding anniversary with William, was hailed as a "peacemaker" after she stepped away after the service to give William and Harry some time to speak alone.
It is said that Charles and his sons had a brief face-to-face chat following the funeral at St George's Chapel on April 17.
Reports have claimed there is still anger and hurt amongst Harry's relatives and there is still some way to go towards healing the rift.
