Kate Middleton has modeled herself after Queen Elizabeth.

The Duchess of Cambridge, 40, has "observed" the monarch as she prepares to take on her future role of Queen Consort.

"Catherine has learned by observing," the Queen's biographer Sally Bedell Smith told People magazine. "She knows what resonates. She will have absorbed a lot from this Queen."

Kate Middleton, Queen Elizabeth

Kate Middleton has "observed" Queen Elizabeth as she prepares for her future as Queen Consort. (Photo by Anwar Hussein)

Royal insiders told the outlet that it is unlikely that the Queen tutored Middleton in any way, but rather treated her how she would prime ministers. They also shared that Middleton portrays Queen Elizabeth's "unofficial motto," which is to "never complain, never explain."

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"The Queen has always preferred to do rather than to say," Sarah Gristwood told the outlet. "With her audiences with her prime ministers, if there has been actual advice, it would be a discreet 'I think that went rather well' rather than actual instruction."

Gristwood, who wrote "Elizabeth: Queen and Crown," praised Middleton’s adaption to the power structure present within the royal family.

Prince William Kate Middleton

Prince William and Middleton have been exercising royal duties while the Queen prepares to leave for her summer holiday in Scotland this week. (Mark Cuthbert/UK Press)

"It's a personal willingness to conform to the requirements of the institution," Gristwood told the outlet. "That sounds like an unappealing, unglamorous virtue, but it's an important one if you're going to be a successful cog in the royal wheel."

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Middleton has been known in the past to replicate some looks that the Queen has worn and even borrowed jewelry from the monarch.

Queen Elizabeth "has this definitive style, almost like a uniform, which also works for Kate," an insider shared.

Queen Elizabeth Platinum Jubilee

Queen Elizabeth celebrated 70 years on the throne in her Paltinum Jubilee in June. (Photo by Chris Jackson)

Bedell Smith shared that Middleton and her husband, Prince William, are "representing the Queen impeccably," while she embarks on her summer holiday at Balmoral Castle in Scotland this week.

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"They're showing a kind of dedication she would be proud of. And that probably gives her hope," Bedell Smith said.

Queen Elizabeth II became the first British Monarch to celebrate a Platinum Jubilee earlier this year after marking 70 years of service to the people of the United Kingdom, Realms and the Commonwealth. 

She celebrated her Platinum Jubilee in June.