Bring back these looks!

In honor of a special cause, Prince William shared a rare throwback photo of himself with brother Prince Harry and their mother, Princess Diana.

On Monday, Kensington Palace shared an Instagram post honoring 999 Day, also known as Emergency Services Day, which celebrates the work of police, fire, and emergency medical services in the U.K. One of the images was of Prince William, Prince Harry, and Princess Diana, with the young brothers playing on a fire truck (in matching blue coats) as their mother watches.

"The first photograph in this post is of The Duke of Cambridge and The Duke of Sussex and their mother Diana, Princess of Wales, with their cousins Peter Phillips and Zara Tindall in the yard of the Old Fire Station 🚒 in the grounds of Sandringham House in 1988," the caption reads.

Also on Monday, Prince William visited a group of firefighters at Harcombe House and launched a texting service through Crisis Text Line in the U.K. that’s specifically for frontline responders.

"As a society, we owe our wellbeing, and indeed our lives, to the men and women in our emergency services who work tirelessly to protect us in some of the most difficult circumstances," he said on Kensington Palace's Instagram caption. "It is only fitting that we should recognize the vital role that they play, and pay tribute to the bravery and dedication of those who have made the ultimate sacrifice for their communities."