Meghan Markle, Kate Middleton have invoked Princess Diana as wives, but her life carries warnings: expert

It’s been 26 years since the world lost the "People’s Princess" – and all eyes are on the royal wives she never met.

Princess Diana, the glamorous mother of Princes William and Harry, died on Aug. 31, 1997, from injuries she sustained in a Paris car crash. She was 36. At the time, the ex-wife of the future King Charles III was being chased by paparazzi.

Years after enduring their mother’s tragic loss, the Prince of Wales and the Duke of Sussex married two different women from two unique upbringings. 

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William married Kate Middleton, the daughter of a flight attendant and a flight dispatcher, in 2011. In 2018, Harry tied the knot with Meghan Markle, a former American actress.

As both women attempted to carve out their identities in the public eye, the wives have continually been compared to Diana, the former nursery schoolteacher who brought lasting change to the royals.

"I’m sure if a poll were taken today, Diana would easily rank as the most popular royal of all time," Christopher Andersen, author of "The King," told Fox News Digital. "Had Diana not entered the picture when she did, I can’t imagine that we would care half as much about the royal family. She breathed new life into what was becoming a musty and outdated monarchy, and continues to even today."

"I think Diana would be thrilled that her sons fell in love with and married two dynamic and fascinating young women," he shared. "Kate is a no-brainer – she fulfills every wish Diana might have had for a daughter-in-law destined to become queen. I think Diana initially would have been happy with Meghan as well, identifying strongly with the divorced biracial American actress as a fellow outsider."

Diana, once called "Shy Di" for her quiet demeanor, transformed herself into a style icon during the ‘80s and ‘90s. She made her mark with couture, which consisted of Chanel suits, Versace evening gowns and Dior handbags. As the most-photographed woman in the world, the royal proved to be influential in both her humanitarian work and personal style.

Middleton, 41, and Markle, 42, have both worn jewelry pieces once owned by Diana and have even emulated her style while publicly supporting their causes.

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"It is well documented that Diana had a difficult time as the wife of our [now] king, but it was perhaps as a result of her suffering that she blossomed so fully, captivating everyone she encountered," royal fashion expert Miranda Holder told Fox News Digital. 

"She may have been downtrodden in her marriage, but when it came to fashion, Diana was unafraid, ripping up the etiquette rule book and curating a catalog of fabulous and, at the time, groundbreaking outfits, each expressing sartorially what she could not verbally," she shared.

"The results were dramatic, raw and unpredictable, and the effect was utterly compelling," Holder added.

But several royal experts agreed that there are warnings to be taken from Diana's brief life.

The Duke and Duchess of Sussex stepped back as senior royals in 2020. At the time, they cited what they saw as the media’s racist treatment of the duchess and a lack of support from the palace. They moved to the wealthy, coastal city of Montecito, California, that year.

In 2021, Markle told Oprah Winfrey in a televised interview that she felt constrained by palace life and that a member of the royal family even asked about the potential skin color of her first child before he was born.

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The couple went on to launch a six-part Netflix docuseries about their life together and Harry released his best-selling memoir, "Spare."

Diana had her own struggles with the palace, airing her grievances in a 1995 BBC interview that continues to make headlines. The network was forced to apologize in 2021 after an investigation found reporter Martin Bashir used "deceitful methods" to secure the tell-all.

During her televised sit-down, Diana said she was "bewildered" by critics who claimed she was "out to destroy the monarchy."

"Why would I want to destroy something that is my children's future?" she said at the time. "I will fight for my children on any level in order for them to be happy and have peace of mind and carry out their duties."

Since the couple made their exit, the relationship between the two brothers has been strained. While promoting his memoir, Harry, 38, told Stephen Colbert that if his mother were alive, "we wouldn’t have got to this moment," adding, "There is no way that the distance between my brother and I would be the same."

"It’s hard to imagine that Diana would have approved of Megxit and the way it pitted her sons against each other," said Andersen. "Harry’s mother always wanted him to have a major role in supporting his brother, the future king. She would never have wanted Harry, no matter how upset his wife had become, to essentially turn his back on his birthright and the rest of the royal family."

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Still, Andersen noted that Diana would "have sympathized" with the pressures the former "Suits" star faced after joining the royal family.

"Diana would have lent Meghan a shoulder to cry on," he said. "I think Diana could also have provided Meghan and Harry with valuable advice on how to cope."

True Royalty TV co-founder Nick Bullen told Fox News Digital that the most important lesson the wives could learn from Diana is simple – duty comes first.

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 King Charles III, Harry's father, for about a decade. He noted that on his streaming platform, Diana continues to be the most popular royal among its subscribers.

"Even Diana at her darkest moments, when things were going very badly for her, she always believed in duty first and [having] a respect for the crown," Bullen explained. "Now there may have been issues between her and her husband, but she always respected the queen."

"Fergie is another great example of this," Bullen pointed out, referring to Sarah Ferguson, Duchess of York, who had a close bond with the late princess. 

"We’ve done a lot of work with Fergie," he said. "She always, and still now, talks about the lessons she learned from the late queen."

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"Both she and Diana believed in duty and respect and loyalty to the crown," Bullen continued. "And I think Kate has done that fantastically. Kate knows she’s got a job to do, and that the job is to support the monarch… It's about supporting the monarch, supporting the crown and being loyal to that entity and understanding the job at hand."

"I’m afraid Meghan hasn’t shown that level of loyalty, respect or duty," he alleged. "And those are probably the things that Kate has learned from her mother-in-law."

But royal expert Richard Fitzwilliams pointed out that the women have carried Diana’s legacy in their own way.

"Whenever Catherine wears a jewel or an outfit as a tribute to Diana, it makes a statement, paying tribute to an icon," he said. "Likewise, when Meghan champions diversity and gender equality, these are areas where Diana would undoubtedly have been thrilled with the progress made since the 1990s."

"I think Catherine resembles Princess Diana when it comes to her passion for family, her passion for children and her fashion," chimed Kinsey Schofield, host of the "To Di For Daily" podcast.

"She has an ‘It’ factor," Schofield shared. "Catherine never engaged with paparazzi, which is very much a lesson that she would have learned from her mother-in-law, who did the opposite. I think we see Diana when Catherine is engaging with her babies in public – sweet, yet stern."

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"I think Diana taught Catherine that royal life is a marathon, not a sprint," she shared. "Kate’s patience and discipline is her not-so-secret weapon for thriving in the royal family. Both Diana and Catherine respect the monarchy and want to see it thrive for a King William reign."

"Princess Diana likely taught Catherine and Meghan to stay true to themselves, protect their peace and prioritize their families," Schofield added.

"Kate… is every bit as glamorous, stunning and stylish as her mother-in-law was," said Andersen. "Kate is no rebel, however, and that’s where Meghan comes in."

British royal commentator Jonathan Sacerdoti told Fox News Digital that one challenge both women will continue to face is stepping out of the shadow of their iconic mother-in-law.

"The legacy Princess Diana has left… is one of awareness," he explained. "Women who marry into the royal family know what they are marrying into, for good and for bad. They make that difficult choice knowing the life of privilege and luxury that they will lead, but also the possible difficulties and challenges that come with all that."

"You can look at her two sons’ wives to see two different ways that can go," Sacerdoti added.

The Associated Press contributed to this report.