Kate Middleton just wore a special accessory during a surprise appearance with Prince William.

On Monday, Aug. 11, the Prince and Princess of Wales, both 42, released a video message in support of Team Great Britain as the 2024 Olympics came to a close. While Prince William’s new facial hair and scruffy look quickly generated buzz, fans also focused on a subtle jewelry swap on Middleton’s hand.

In place of her iconic sapphire-and-diamond engagement ring, Kate wore a gold band encrusted with white diamonds and sapphires—a more casual alternative to the engagement ring that once belonged to William’s late mother, Princess Diana.

The new accessory, a thick gold ring studded with diamonds and sapphires, is believed to be a promise ring from William, given to his wife during their early romance while they were students at the University of St. Andrews in the early 2000s.

Well done @TeamGB, what an incredible journey!

Every athlete showed immense dedication, heart and passion. You made us all so proud!

Here’s to celebrating every triumph at @Paris2024 and looking forward to more from @ParalympicsGB later in the summer ??? pic.twitter.com/oCLz7HuuLG

— The Prince and Princess of Wales (@KensingtonRoyal) August 11, 2024

According to the site Dress Like a Duchess, long before Prince William proposed with his mother’s famous sapphire and diamond engagement ring in 2010, he gave Kate this pearl and garnet rose gold promise ring similar to the Victorian rose gold band, adorned with pearls and garnet—symbolizing their birthstones—which appeared in the video. (The pearls represent William’s June birthday, and the garnet symbolizes Kate’s January birthday.)

Kate first wore this ring in June 2005 on her graduation day from St. Andrews, where she earned a degree in art history. At that time, she wore the ring on her middle finger during her youth. The ring signified “commitment and fidelity as well as a pledge for lifelong love and loyalty,” according to Dress Like a Duchess.

Tatler noted that the garnet gemstones in the promise ring “are said to represent commitment, and pearls are known to be a symbol of innocence and purity.”

It isn’t clear when Kate received her new eternity band, but some fans speculate it may have been a present from William to mark their 13th wedding anniversary on April 29.

“From all of us watching at home, congratulations to Team GB,” Kate said. William added, “Well done on all you have achieved. You’ve been an inspiration to us all.”