Kate Middleton as future queen makes key decisions to protect royals: expert

Princess Kate Middleton has been preparing for her future role as queen consort, and so far, she's been successful.

True Royalty TV co-founder Nick Bullen told Fox News Digital that the Princess of Wales has been described as the "power behind the throne" by those who work closely with her.

The streaming platform has a new documentary, "Catherine: Our Queen in Waiting," which explores how Prince William’s wife has charmed palace aides, the public and the press over the years.

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"The interesting thing about Kate, the Princess of Wales, is her steeliness," Bullen said. "She is a very strong character who has transitioned from being a young bride to being a key player within the royal family. ... If you look at all the photographs now, she’s always front and center. She looked amazing at the coronation, she looked incredible at Ascot. She’s now every inch the princess. And I think at the coronation, everyone agreed that she looked very much the next queen."

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"This hasn’t happened by accident," he said. "She is a clever, smart, determined woman. And I’m told by people who work at the various palaces that she is quite literally the power behind the throne."

Bullen is an award-winning documentarian who has been producing programs about the British royal family for 20 years. He has also worked closely with the king for about a decade.

Bullen said that many senior royals have taken inspiration from the glamorous mother of three, who has modeled herself after Queen Elizabeth II. Britain’s longest-reigning monarch died in September at age 96. And as future queen consort, the princess is said to be hands-on in making key choices about the family to protect and preserve their image. And William gives her free rein.

"I think a lot of the members of the family look to her, including William, obviously," he said. "I believe she is involved in making quite a lot of the decisions on how things move forward and how the family is portrayed. … She just continues to get better and better."

On Friday, Buckingham Palace and King Charles announced new military appointments for nine members of the royal family, including the 41-year-old princess. She’s now commodore in chief of the Fleet Air Arm, colonel in chief of the 1st Queen’s Dragoon Guards and royal honorary air commodore of Royal Air Force Coningsby.

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The last appointment hits close to home. Her grandfather, Capt. Peter Middleton, served in the Royal Air Force (RAF), People magazine reported. According to Hello! Magazine, the patriarch flew as a co-pilot with the late queen’s husband, Prince Philip, during an aerial tour of South America in 1962.

But the princess has made her mark in other ways. Bullen described her as a "brand powerhouse" whose personal style features recycled luxury labels and affordable brands. The "Kate Effect" started in 2010 when she first wore a blue wrap dress for her official engagement portrait. Since then, royal watchers and fans have immediately sold out pieces that mimic her highly photographed style moments.

It’s noted that the royals have often used fashion to send subtle messages. Bullen said the princess has relied on her style to make herself appear approachable while symbolizing the monarchy’s future. It has also garnered positive publicity for the royals after months of public drama.

"I think she’s clever … with the way she uses her fashion," he said. "She has incredible outfits. Who can forget that gold dress from the Bond premiere? I was with her recently at the BAFTAs, and she turned up in a dress she’d worn before but with High Street earrings. I think she’s very good at playing the messaging that’s required at the time. That’s her compass. She’s a branding superpower."

Middleton has been described as "Britain's reliable royal." After the Duke and Duchess of Sussex's stormy departure to California in 2020 and the sex abuse allegations against Prince Andrew, the princess has remained in the public eye as a smiling matriarch dedicated to duty. She has won accolades for her commitment to early education, art and music. The charities she supports have also gushed about her willingness to get personally involved in their causes.

The Prince and Princess of Wales first met as students at the University of St Andrews in 2001. During their engagement interview, William, now 41, said they were friends "for over a year first" before a romance blossomed. They split up briefly in 2007 before getting back together. William later acknowledged that the couple’s romance wobbled for several months, saying they were both young and trying to find their way. During that time, the tabloids dubbed her "Waity Katie" for her patience during their courtship.

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William proposed in 2010 and the couple married the following year.

Bullen said William has been by his wife’s side over the years as she navigates royal life, making sure she’s up for the job. He also learned vital lessons from the doomed union of his parents. The king and Princess Diana divorced in 1996 after a messy and oftentimes public breakdown of their marriage. Diana died in 1997 at age 36.

"William has been very good at making sure both Kate and the children have a [normal] life," he said. "He was in the limelight from the moment he was born. And I think that’s one of the things he’s been very clear about doing … he wants as much normality in there. And I think giving normality is what’s allowed Kate to really grow into the role and will also be really effective for the children. … That has come through in her confidence."

Bullen said William has allowed his wife to shine during public appearances.

"Look at her at Wimbledon and the way she was hugging the players there," he said. "… She’s the patron of it. William allowed her to be in front and lead the way. And I think that’s been an interesting story in their relationship. Although he’s officially the more senior [royal], and normally she’s walking a few steps behind him, when it’s her moment, things like Wimbledon, he allows her to have that moment."

"I think it’s those two things," said Bullen. "I think it’s giving her time to grow into the role and then acknowledging that there are moments when she has to take the lead. And she takes them very well."

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All eyes will continue to be on the princess. But Bullen believes the monarchy’s future is in safe hands.

"The Prince and Princess of Wales’ lives have changed enormously since the death of the queen," Bullen previously told Fox News Digital. "The moment William became next in line, everything changed. He was always serious about his duty, and he always knew what his destiny was, but now it’s there. … I think you can see the seriousness in the Wales in a way that wasn’t there even a year ago."

"We’ve recently been working with him in his role as president of the BAFTAs," Bullen continued. "And it was very interesting – his whole demeanor was, in some ways, more serious than I’d seen it before. The things that he wanted to be involved in were very serious causes that had a real purpose. He doesn’t really want to talk about himself. The Princess of Wales doesn’t want to talk about herself. They want to really focus on the causes and the things that are important to them, as opposed to about them."

The Associated Press contributed to this report.