A royal expert is speaking out this week to say that Kate Middleton, who is the wife of Prince William, has managed to earn the approval of Queen Elizabeth and Prince Philip for one reason.

“I think that both Queen Elizabeth II and Prince Philip probably get on their knees and pray to God, ‘Thank you for sending us Catherine Middleton,’” longtime royal biographer Ingrid Seward told Fox News. “She is a gem.”

Middleton has been married to William since 2011, and she has developed a particularly close bond to the Queen in that time.

“She’s gorgeous and never takes a bad photograph,” Seward explained of Middleton. “And in this visual world that we live in, it’s important to see someone who’s going to be a future queen as a beauty, which she is. But she also works hard. She’s brought a breath of fresh air into the Windsor family.”

“I’m certain she has her faults, but she doesn’t show them,” she added. “And it’s known that Philip likes her too. She’s a little bit more of an old-fashioned girl than Diana or Meghan Markle, which I think he appreciates.”

Other royal experts agree that Middleton has easily won over the royal family with her grace and her calm demeanor.

“Kate has been a perfect [companion] because she’s so calm and stable — and that’s what he needs,” said royal author Tom Quinn. “I’m not saying she’s sort of a second mother, but there’s an element of that. She’s… a rock. It’s a bit of a cliche, but she’s someone who just doesn’t have a history that’s all over the place. She’s very calm, very rational. And I think that’s why the royal family feels safe.”

“She also does something which is absolutely key to being happy while also being a member of the royal family,” he continued. “Whatever the press may say about you, you don’t complain and you don’t explain. And Kate is very good at that.”

William and Middleton met back in 2001 when they were both students at St. Andrew’s University in Scotland. They have since gone on to have three children: Prince George, 7, Princess Charlotte, 5, and Prince Louis, 2.