"The future Queen is a role model to the U.K. but also to the world, which means all eyes are on you," royal etiquette expert Myka Meier tells PEOPLE

Kate Middleton is back to public duty after a three-month pandemic lockdown — and she and Prince William are adjusting to the void left by Prince Harry and Meghan Markle’s departure from royal life.

As the mom of three, 38, steps back into the spotlight, she faces mounting public expectation as future Queen. And she finds herself trying to do it all at a time when the public is reexamining old institutions and their place in modern society.

“Those who know her say there is a real core of strength, and she did set her mind to the job,” Sarah Gristwood, author of Elizabeth: The Queen and the Crown, tells PEOPLE in this week’s cover story. “But at the same time, she’d have to be superhuman not to feel the pressure.”

The exit of the Duke and Duchess of Sussex thrusts the future Queen Catherine even closer to the center of the royal family.

“Without Meghan and Harry, there is going to be a phenomenal workload on Catherine and William,” says a source close to the royal household. “None of the older [generations] can do it all. The pressure is on the two of them.”

princess kate
Kate Middleton

The unprecedented shift has brought renewed scrutiny, including a recent cover story in the U.K.’s Tatler magazine claiming that Kate felt stressed and overwhelmed by the vacuum resulting from Harry and Meghan’s exit. In a rare statement, the palace promptly blasted the story’s “inaccuracies” and threatened legal action against the publication.

Kate “certainly would resent someone saying that she is struggling,” says a close source. “I can understand why she would feel that is a total misrepresentation of the truth, because it really isn’t the case. If anything, she is relishing the role more than ever. And she will do it all to the best of her ability.”

Royal visit in Norfolk
Kate Middleton on June 18
| Credit: PA Images

As the future Queen raising a future King, Kate is expected to flawlessly fulfill multiple roles: princess, supportive spouse, hands-on mom, international bridge-builder, charity advocate, style icon and more.

“The future Queen is a role model to the U.K. but also to the world, which means all eyes are on you,” says royal etiquette expert Myka Meier, author of Modern Etiquette Made Easy. “The added pressure of having cameras everywhere to catch even the slightest eye movement makes everything she does a conscious effort. From the perfectly poised posture to the way she descends a staircase or gets out of a car—it is all carefully done.”

princess kate

The global scrutiny means that even her style choices carry enormous weight. That expectation extends to her kids — Prince George, 6, Princess Charlotte, 5, and Prince Louis, 2, as well.

“I think the pressure is more about her public image, making sure she is wearing the right brands, showing the kids in less expensive clothing, especially right now,” says an insider. “Small details, but they matter.”

Cambridge family
Prince William, Kate Middleton, Prince Louis, Prince George and Princess Charlotte
| Credit: BBC

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Like Queen Elizabeth, Kate doesn’t let the pressure show. And she has found increasing confidence with her royal work, which has helped propel her forward.

“Catherine is the sort of woman who will take on whatever she needs to,” says the close source. “If she needs to step up to the plate, she does it—and she always has.”

  • with additional reporting by Monique Jessen and Phil Boucher