The family of five stepped out for the first time looking picture flawless.
In 2015, his sister Princess Charlotte was christened at St. Mary Magdalene Church in Sandringham, a royal estate near England's eastern coast.
Prince Louis' Godparents Revealed - See the Full List!
The royal family ― sans Queen Elizabeth II and Prince Philip ― showed up for Prince Louis Arthur Charles' christening on Monday. The Queen , 92, and the Duke of Edinburgh, 97, did not attend, in what was described as a "mutual decision" made some time ago.
Kate has been on maternity leave since the birth of Prince Louis, who was born on April 22, 2018.
Prince Louis sleeps through his royal christening.
However the Queen, 92, and Prince Philip, 97, were notable absences as it was confirmed that they were unable to attend the christening service due to their busy royal schedules.
The 40-minute ceremony will be conducted by the Archbishop of Canterbury, the Most Reverend Justin Welby, who was also involved in the wedding of Prince Harry and Meghan Markle in May.
If some of the name sounds familiar, it's because several members of Prince Louis' list are related to godparents chosen for the other tiny royals.
Princess Charlotte wore a blue smock dress and matching bow headband.