Prince William and Kate Middleton’s ‘genuine love story' is built on being a 'very normal family': author

Prince William and Kate Middleton are marking a special milestone.

The Prince and Princess of Wales, who are celebrating their 15th wedding anniversary on April 29, took to social media to share a photo of themselves relaxing on the grass with their three children: Prince George, 12, Princess Charlotte, 10, and Prince Louis, 8.

The family smiled as they snuggled together.

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"Celebrating 15 years of marriage," the caption read, alongside a heart emoji.

The anniversary comes after a difficult stretch for the royal family, as Kate gradually returned to public life following her cancer treatment and William continued balancing royal duties with family responsibilities.

William met Kate when they were both students at the University of St. Andrews in Scotland. They dated on and off before getting engaged in 2010. They married a year later at Westminster Abbey.

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"I think with William and Catherine, it really is, unquestionably, a genuine love story," Robert Hardman, author of "Elizabeth II: In Private. In Public. Her Story," told Fox News Digital.

"It had to be conducted in the full gaze of media scrutiny, but they’re a great partnership, and they’re a very close family," he shared. "It’s interesting that they like nothing more than being together in relatively ungrand situations. They don't have a great desire to stay in five or six-star hotels, and they don’t live a very grand life. Their idea of fun is just going for a picnic in the woods of Norfolk or spending time at home in the garden."

"They’re a very normal family," Hardman added.

British broadcaster Helena Chard told Fox News Digital the couple is expected to celebrate privately, likely outdoors with their children.

"Understandably, they’re keeping things under wraps," said Chard. "It avoids splitting coverage from King Charles and Queen Camilla’s state visit. But no doubt they will celebrate as a loving family behind closed doors, allowing the state visit and the U.K. and U.S.’s shared history and friendship to take center stage."

Hardman noted that there’s one thing William has made clear over the years — his family comes first.

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"They’re a regular family, and I think they’ve shown time and time again that when there’s a family issue, family, for him, comes first," he explained.

"There have been moments where he hasn’t been at events," said Hardman. "People said, ‘Well, where’s Prince William?’ And they learned his wife wasn’t feeling well, or he was taking the children somewhere."

"We’re all looking at what William will be like when he’s king," Hardman shared. "In his approach to the job, he takes his role as father very seriously.

"He’s not just a future king, but he’s the dad of a future king. I know he’s very concerned about how to make the whole royal experience as un-scary, if you like, and as appealing as possible, notably to his oldest son, George, but to Charlotte and Louis as well, because they are the future of the monarchy."

"If they decide they don’t want anything to do with it, then it’s very bad news for the monarchy," said Hardman.

In a 2024 interview on "The Reluctant Traveler with Eugene Levy," William, 43, opened up about how he prioritizes his family.

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"I do try and stick to school timetables as best as possible," he said. "So, most days we’re in and out of school doing pick-ups and drop-offs."

"Getting the balance of work and family life right is really important because, for me, the most important thing in my life is family, and everything is about the future. ... If you don’t start the children off now with a happy, healthy, stable home, I feel you’re setting them up for a bit of a hard time and a fall."

William and Kate have discussed their love of spending time outdoors. In a 2020 podcast, Kate said her favorite moments with her family take place "outside in the country, and we’re all filthy dirty."

Chard said the couple’s focus on family has remained central to their relationship.

"The bond and love that the Prince and Princess of Wales still share is evident for all to see," Chard previously told Fox News Digital. "They complete each other like two puzzle pieces. They are soulmates. The truth is, both Prince William and Princess Catherine have always had a strong sense of self. They communicate, compromise and share burdens. They help each other through challenging times."

"Their shared humor is also their superpower, along with a wonderful circle of friends and a strong family support network," said Chard.

 "They don’t feel the need to prove themselves to anyone and are laser-focused on all they do, from their family priorities to their royal endeavors. They haven’t changed as people and have simply matured together. They certainly know their own minds and, as modern royals, are carrying out everything that they feel fits rather than what is expected."

"They prioritize shared goals in bringing up a happy, healthy family," Chard added.