Prince Harry reveals why Kate Middleton and Meghan Markle are feuding in his autobiography Spare

Prince Harry has revealed what’s behind the explosive falling out between Meghan Markle and Kate Middleton, savaging the Princess of Wales in the process.

Prince Harry has revealed the source of the bad blood between the Royals.

The Duke of Sussex has “hammered” the Princess of Wales, revealing spats over a shared lipgloss, Easter presents, a bridesmaid’s dress and his wife Meghan calling her “baby brain” when she was pregnant caused the two women to feud.

In his memoir Spare, Prince Harry takes an unreserved swipe at the “sister he never had,” saying Kate, 40, and the Duchess of Sussex, 41, have fallen out over the years and relations remain frosty.

Writing in extraordinary detail about how the women have clashed, he says Meghan asked to borrow a lip-gloss from Kate ahead of their appearance at the first Royal Foundation forum summit in 2018, leaving the latter grimacing with disgust.

Relations between Kate and Meghan are ‘frosty’. Picture: Gareth Fuller/PA Wire

Kate was surprised, he writes, but rummaged around in her bag before offering it to Meghan.

Harry claims the Suits actress applied a little gloss to her finger, and smeared it across her lips, before Kate pulled a “disgusted” face.

The summit was William, Kate, Harry and Meghan’s joint venture and aimed to galvanise the star power of the foursome.

At the time, Harry said “working as a family does have its challenges” but maintained “we’re stuck together for the rest of our lives’.

Harry was quick to concede there were “healthy disagreements” and joked they “come so thick and fast” when asked what the last thing they quarrelled on was.

William continued the banter, joking, “Is it resolved? We don’t know!”

Elsewhere in the book, released on Thursday in Spain ahead of its worldwide publication date on Tuesday, he reveals both women were left in tears during the infamous bridesmaid dress row.

In a phone call to discuss the Sussex’s 2018 wedding arrangements, Meghan commented that Kate must have “baby brain” while pregnant.

Press reports saying the women clashed over bridesmaid dresses claimed Meghan was the one who had made Kate cry and the Sussexes were furious the palace did not release a statement correcting what happened in the row.

One unnamed friend claims Kate wanted to follow “protocol”, with the bridesmaids, including Charlotte, then aged three, wearing tights, but Meghan disagreed. The women also disagreed over the length of Princess Charlotte’s hemline and the fit of her dress. Harry added that Kate arrived at the house the next day with a card and apology flowers. Meghan described the episode as a ”turning point” in the women’s relationship.

According to Harry, after he and Meghan’s honeymoon, the Prince and Princess of Wales invited Harry and Meghan to their flat at Kensington Palace in a bid to fix the growing rift between the couples. Harry writes that upon entering the flat, Meghan’s mouth gaped open at the smart decor, priceless art on the walls, books and furniture, exclaiming “wow” repeatedly.

Harry said their nearby flat was kitted out with Ikea lamps and furniture bought on sale with Meghan’s credit card.

Harry wrote that there were further issues – including William and Kate feeling aggrieved they hadn’t received a gift for Easter.

In his autobiography, Prince Harry claims at the Kensington flat reunion, William told Meghan she wasn’t close enough to Kate to make flippant remarks and that Meghan apologised saying that is how she speaks with her friends.

Prince Harry writes William “pointed a finger at Meg”, then allegedly said: “Well, it’s rude, Meghan. These things are not done here.”

To which Meghan responded: “If you don’t mind, keep your finger out of my face.”

Royal commentator Richard Fitzwilliam told News Corp Australia: “This is all about jealousy and the Duke of Sussex hammers everyone, no one escapes. There is no going back for him now, no matter how many times he says he wants a reconciliation.”