Kate Middleton has been paying tribute to her late mother-in-law, Princess Diana, over the years.

The late Princess of Wales would have turned 57 years old on Sunday if she had still been alive. To celebrate Princess Diana's birthday, Hello! compiled several photos of the Duchess of Cambridge and how she paid homage to the People's Princess, especially when it comes to her kids.

when Middleton welcomed Prince George in 2013, many likened her Jenny Packham polka dot dress to Princess Diana's when the latter presented Prince William to the world. In addition, the duchess takes cues from Princess Diana when it comes to dressing her children, especially Prince George.

"Diana dressed Prince William in a very traditional way, even more traditional than Kate does with Prince George," Rachel Riley said. "George always looks gorgeous, too. His clothing is very classic but suitable for today, that's the look they are trying to achieve. It's a more modern version of William's look when he was a little boy."

Prince William and Middleton also considered Princess Diana after welcoming their daughter, Princess Charlotte. The Duke and Duchess of Cambridge opted to name their daughter Charlotte Elizabeth Diana. They also held Princess Charlotte's christening in St. Mary Magdalene Church. It's the same church where Princess Diana was christened in August 1961.

In 2016, Middleton attended the annual Commonwealth service and wore a traditional hat designed by Princess Diana's favorite milliner John Boyd. Many believe that the royal mom's choice was a nod to Princess Diana. According to Boyd, he has started working for the royal family in 1967 and his popularity peaked when the late Princess of Wales sported his headpiece.

Prince William confessed that he was sad that his mom was not able to meet his wife in person. The duke was hoping that Princess Diana would be proud of them.

"I think she would have loved the day and I think, hopefully, she'd be very proud of us both for the day. I'm just very sad that she's never going to get a chance to meet Kate," Prince William said.

Prince William just visited Jordan and according to him, Middleton was upset that she was not able to accompany him on the said trip. The Duke of Cambridge paid a tribute to his wife by recreating Middleton's childhood photo in Jerash.

Kate Middleton Kate Middleton has been paying homage to Princess Diana in several ways over the years. Pictured: Middleton attends the 100th anniversary of the beginning of the Battle of the Somme at the Thiepval memorial to the Missing on July 1, 2016 in Thiepval, France. Photo: Getty Images/Phil Noble