Kate Middleton has allegedly begged Prince Harry not to tarnish Prince William's image in his upcoming memoir called "Spare."

The Princess of Wales is reportedly desperate for her husband to keep a clean image since he will become king one day. But the fact that her brother-in-law is releasing a book that contains "raw, unflinching honesty" has her worried. A source claimed that the memoir could likely include stories about Prince William since the Duke of Sussex "holds the key to a royal safe full of William's secrets, and now he may expose them."

"William and Harry were inseparable when they were younger and hung out in the same crowd as teens. Harry could easily discuss William's boozy nights and one-night stands," the insider told In Touch USA in its Nov.14 issue, adding that "William had a wild streak too, which is worse than anyone knows. Then there are the rumours about William's cheating scandal and marital woes."

The source claimed that Prince William "feels completely betrayed" by his sibling and claimed that the "conflict between the brothers has rocketed into a full-blown war." But the 40-year-old is "too hard-headed" to initiate a truce before Prince Harry releases his book on Jan. 10, 2023, just a day after Kate Middleton's birthday.

However, the Princess of Wales is "desperate to do damage control." She allegedly banked on her "special bond" with Prince Harry and asked him to spare his older brother from his memoir. The source claimed that she "reached out to him and begged him not to destroy her husband."

The Duke of Sussex "has a soft spot for Kate, which is why he still takes her calls." The source claimed that the princess "can empathise with his frustrations, but she pleaded with him not to take them out on William" because this could only "ruin the brothers' relationship forever."

However, readers have yet to find out what Prince Harry wrote in his memoir. Royal author Omid Scobie believes that "Spare" will not trash the royals, including Prince William. But he warned that its contents still pose a "very real risk of serious blowback from the institution and family."

Meghan Markle and Prince Harry
Prince William, Kate Middleton, Prince Harry and Meghan Markle at the walkabout outside Windsor Castle on Sept. 10, 2022. Photo: Chris Jackson - WPA Pool/Getty Images/Getty Images Chris Jackson - WPA Pool/Getty Images/Getty Images