Archbishop of Canterbury Justin Welby, the spiritual leader of the world's Anglicans, will lead the service in the Chapel Royal at St James's Palace.
His eldest sibling Prince George, 4, clutched his dad Prince William's hand and had his trademark look of vague distaste on his face (god I love this kid) while sister Princess Charlotte, 3, looked mostly confused.
Meghan Markle Goes for Green at Prince Louis’ Christening
During the event, one hundred RAF aircraft will fly across England to celebrate the Royal Air Force's 100th anniversary. Meghan opted fro an olive green Ralph Lauren dress, which featured a boatneck and a matching hat by Stephen Jones .
The final guests were the young prince's six godparents and their spouses, all of whom are friends or family of the Duke and Duchess. Prince Louis godparents are Lady Laura Meade, Hannah Carter, Lucy Middleton, Nicholas van Cutsem, Harry Aubrey-Fletcher and Guy Pelley.
The little prince was also christened in the Lily Font, a silver gilt font and bowl decorated in lilies, ivy and cherubs.
The Middleton family was also represented, with Louis' pregnant aunt, Pippa Middleton Matthews, at the intimate gathering.
George Clooney reportedly injured after motorbike crash in Sardinia
The paper also tweeted a photo of his scooter abandoned by the side of the road with a Mercedes estate vehicle just feet away. According to the site, George was said to be hit by a vehicle which suddenly changed direction at a spot close to a hotel.
Thankfully for the Duke and Duchess of Cambridge, Louis was very well behaved during his eagerly anticipated christening, and the 11-week-old stayed fast asleep as his mum carried him into the chapel. While some fans might have expected Prince Harry and Meghan Markle to be chosen for this role, the newlyweds did not make the cut.
According to reports, Queen Elizabeth II then asked her personal dresser Angela Kelly for a replica of the gown to be made.
Click through the slideshow to see who has been named a godparent to Prince Louis...
Jamie Vardy sends Gareth Southgate update ahead of World Cup semi-final
Picture of the day Man of the moment Harry Maguire , who scored his first worldwide goal against Sweden, takes to the oche. But this is our family now. "You wouldn't have said we were going to win beforehand", Hurst added.