Princess Kate's secret 'Queen masterplan' exposed

Princess Kate carefully planned her rise to the top royal role as she was "born to lead the monarchy," according to royal experts.

Prince William's wife played the long game with patience and wisdom, fully preparing for her key future role as Queen. She believed in steady progress as she learned the ropes of royal life.

Royal author Simon Vigar wrote in "The Four Wives of Windsor" that William's "right-hand man" said: "Catherine is no wallflower."

Vigar, in conversation with Fox News Digital, reveals the Princess of Wales' masterplan, saying: "She's got definite views about things. William obviously trusts her implicitly, and they need people like that. The queen needed Philip. Charles needs Camilla. And William needs Catherine. [And] she's very clever. I reckon she's probably the cleverest of a lot of them."

She was determined to master the role, carefully carving out her place without overshadowing the monarch.

The royals had various charitable interests, ranging from wounded service personnel to early years education and homelessness. The person who linked all of those together under the mental wellbeing banner was Catherine, according to the author.

 "It wasn't Harry or William. She was the one who said, 'Do you know what the common denominator with all of this is? It's mental wellbeing and mental health,'" claimed Vigar.

Undoubtedly, Catherine's the person that William can trust absolutely implicitly to give him impartial advice. Kate's journey to becoming the Princess of Wales was unlike that of the royal women who came before her.

"It’s a huge social leap that happened with Catherine," said Vigar. "Lady Diana Spencer was a member of the aristocracy. Camilla’s pretty posh, as we say in this country, not quite as posh as Diana, but posh."

"Catherine's middle class," he continued.

"Her parents worked very hard. They built their own business. They were able to send their children to private school. ... And it got her to St. Andrews University, where she met William, of course."

Since her marriage to William in 2011, Kate has devoted herself to several charitable causes and organisations focused on early childhood development, mental health, sports and the outdoors among others.

"I think Kate was born for this role, as odd as that may sound.  She has a preternatural calm, a sense of self and confidence that borders on regal. I think she could have stepped into the role as queen-in-waiting back when she was still a student at St. Andrews University," According to the expert.

He went on: "It was William who dragged his feet and gave Kate 10 years to learn the ropes before popping the question."

Kate's innate grace and charm inspired several royals. She knew intuitively when to hold back, when to get along and when to stand her ground.

"Kate and William are determined to shape their own destiny. They want to be avatars of change. They don't want the monarchy to become so hidebound that it collapses from its own weight," Andersen said.

Several other experts and historians describe Kate the monarchy's most important asset.