William and Kate were married on April 29, 2011 at Westminster Abbey in front of a global audience of hundreds of millions.
Body language specialist Judi James compared the new photos with previous pictures of the couple together.
Speaking to the Daily Mirror she said: “The couple in the most recent photos though are people you’d want in your social bubble, popping in for drinks around the BBQ.
“Happy and incredibly relaxed together, they look like they’d be the best fun.
“Some couples grow apart during a decade of marriage but William and Kate’s body language suggests they have grown closer and learned to enjoy life openly and with confidence.”
William and Kate have three children; Prince George, Princess Charlotte and Prince Louis.
The young royals were born in 2013, 2015 and 2018 respectively.
“Ten years ago they looked in love and Kate’s smile showed excitement at the thought of the wedding.
“Now they look in love and in the middle of a life of shared, playful fun where William has been able to drop his reserve and his ego and enjoy the fact that he and Kate are a solid working team as well as a mutual support system.”
The Duke and Duchess thanked the public for their support over the past decade via the official Kensington Palace Twitter account.
They wrote: “Thank you to everyone for the kind messages on our wedding anniversary.
“We are enormously grateful for the 10 years of support we have received in our lives as a family.”
This was accompanied by a video showing William and Kate playing with their three children in a variety of outdoor locations.
The clip has been viewed over half a million times and received more than 60,000 likes.
Ms James claimed the Duke and Duchess appeared more “distanced from the audience” in photographs taken in 2011.
She commented: “In the early photos we can see a couple looking excited and in love, whether they’re snuggling up using head closeness to signal cute levels of affection or following royal tradition with a much more formal look that is all about elegant sophistication and high status.
“The couple look blissfully happy together but rather distanced from the audience.
“William’s mouth-smile is wide but his eyes look slightly wary, not of Kate but of the camera and the attention.”