One person wrote: “Prince Louis growing up. In long trousers (jeans even) and awaiting new front teeth. Terrific photo. Wishing Louis a fun family day, a delicious homemade cake and a great year.”

Another commented: “He’s suddenly all grown up. Happy birthday to Prince Louis!!”

A third added: “Wow, so grown up all of a sudden! Happy Birthday Louis.”

And someone else said: “Wow! 7 y/o already!? Time flies. Happy Birthday Prince Louis!! Hope you have a wonderful birthday!”

Prince Louis was born at 11:01 a.m. on April 23, 2018, at St Mary’s Hospital in London. His birth certificate is slightly different from those of his brother and sister.

His full title on the certificate is ‘His Royal Highness Prince Louis Arthur Charles of Cambridge’, which follows the same style as his siblings. George was listed as ‘His Royal Highness Prince George Alexander Louis of Cambridge’, and Charlotte as ‘Her Royal Highness Princess Charlotte Elizabeth Diana of Cambridge’.

The last part of the trio’s name could also be changed to “of Wales,” since their father, Prince William, became the Prince of Wales after his father, King Charles, took the throne when Queen Elizabeth II passed away in 2022.

On all three of the children’s birth certificates, Kate is listed as “Her Royal Highness Catherine Elizabeth, The Duchess of Cambridge,” while William, now 42, is listed as “His Royal Highness Prince William Arthur Phillip Louis, Duke of Cambridge.”

But there’s an interesting difference in how the documents were signed. For George and Charlotte, the certificates were signed by hand.

In contrast, Louis’ certificate was signed digitally, which means it was likely filled out on a computer by a different registrar.

According to Town & Country, this might simply come down to a “matter of preference” depending on who had the job at the time—some may prefer typing it, while others write it by hand.