The close bond between father Prince Charles and son Prince William is due to Princess Kate, according to a new biography about her.

According to an excerpt from Robert Jobson's forthcoming book, “Princess Catherine,” Kate Middleton is a “calming influence” on the entire royal family, especially her husband Prince William.

The excerpt, obtained by the Daily Mail, claims that Middleton is an “instinctive peacemaker” who has, in effect, “smoothed the way for William and his father to have a better relationship than in the past.”

“They have grown closer in recent years,” a senior source quoted in the biography says of Prince Charles and Prince William's relationship.

“He also respects his father and his dedication to service, but he feels that his father's work-first attitude had a detrimental effect on him growing up and did not help the parent-child relationship,” this source added.

According to the same source, Princess Kate helped her husband see things through his father's perspective.

“[Queen Kate] is someone who always tries to see both sides of any conflict,” the source claimed, adding that she is “emotionally mature” and a “stabilizing influence” on the monarchy, certainly when it comes to her husband and his (sometimes) turbulent family relationships.

While the biography highlights how the Crown Princess influenced her husband, it also pulls back the curtain on how Prince William influenced his wife, particularly in the wake of her cancer diagnosis and ongoing treatment.

His influential support was highlighted by Middleton herself, who told the world upon announcing her diagnosis that “having William by my side is also a great source of comfort and reassurance.”

“So is the love, support, and kindness that so many of you have shown me. It means so much to both of us,” she continued at the time.

After his wife's cancer diagnosis, and the tampering of Mother's Day photos of Princess Kate and their children, and the onslaught of conspiracy theories, Prince William reportedly felt “guilty” for failing to “protect” his wife from the media and social media onslaught.

“William would have shown only support and kindness to Kate after this latest setback,” a royal expert said at the time OK!

“William is definitely frustrated about the incident. He's not frustrated with Kate, he's frustrated that such a ridiculous fuss was made over nothing and that everything was pushed through.

“He also promised Kate's parents that he would protect her and take care of her, so he will feel guilty about any hardship she goes through.