Prince Louis' Easter outfit in style for the first time

Anyone who knows anything about the royal family knows that there are rules, procedures, and precedents for everything. The same goes for the attire of young boys, like Prince Louis, who made his royal Easter debut this past Sunday at St. George's Chapel in Windsor. (Prince Louis attended church with his entire family of five: his parents, the Prince and Princess of Wales, and his older siblings, Prince George and Princess Charlotte.)

Louis, who turns five in a few days on April 23, wore sky blue shorts by British children's designer Rachel Riley, who also designed Charlotte's floral dress.

"It was wonderful to see the three royal children join their parents for the traditional Easter Sunday service in the spring sunshine," Riley tells People. 'We were delighted to see Princess Charlotte in our navy mini floral ruffle dress. The printed cotton dress with puff sleeves and Peter Pan collar is perfect for a girl her age. The blue and ivory floral print on a navy background coordinated perfectly with the rest of her family. They were all in blue and very harmonious."

Louis stuck to the standard British upper-class boys' style of shorts and knee socks, People reported. On Sunday, however, he wore a tie and blazer for the first time.

"Prince George is wearing long pants now that he's older," Riley said.

"And the fact that the Crown Princess chose sky blue instead of navy made her outfit more fun and age-appropriate. It also matches her mother and sister perfectly, which is something we can still do as the youngest siblings."

And if you look closely, Louis' tie was a bicycle pattern. Recalling his third birthday portrait, released almost two years ago, who could forget the snap his mother took of him on his first day at preschool, where Louis posed adorably on a red bicycle?