Catherine and William paid this sweet tribute to Prince Harry with Prince Louis' outfit

At yesterday's Trooping the Colour, the Duke and Duchess of Cambridge's youngest child, Prince Louis, made his debut on the balcony of Buckingham Palace.

The adorable one-year-old could barely contain his excitement at the goings-on, including the overhead fly-past, happily waving his arms about and clapping his hands together.

But eagle-eyed royal fans would have also noticed a sweet tribute to his uncle, Prince Harry, within Prince Louis' outfit.

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It seems as though Catherine and William decided to dress their baby son in an outfit that previously belonged to Prince Harry.

Louis' adorable blue shorts and white shirt with blue pattern has actually been seen before on his uncle, during the 1986 Trooping the Colour.

In picture, a two-year-old Prince Harry can be seen being carried by his auntie Princess Anne, looking just as sweet as the youngest Cambridge did yesterday.

The royal family will ocassionally recycle children's outfits in this same way, although we haven't seen the Cambridge kids rewear an outfit for some time.

So we're sure Prince Harry enjoyed this rare reminder of years gone by!

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Yesterday's Trooping the Colour saw almost the entire royal family turn out to celebrate the Queen's official birthday.

It was Prince Louis' very first official royal engagement, and one of many to come for the littlest Cambridge.

The Duchess of Sussex returned briefly to her royal role for the family event - her first public outing since the birth of hers and Harry's son, Archie, just over a month ago.

She looked glowing in a navy Givenchy coat and dress, as she, Prince Harry, Camilla, and the Duchess of Cambridge rode in a carriage together during the parade.

It's likely that Meghan will still be taking the next few months off of royal duties for her continuing maternity leave, but it's thought that she made an exception for Trooping the Colour as it is such an important family day.