Prince Louis' royal christening: All the best photos from the unforgettable day

The British royal family stepped out in impeccable style to attend the christening of baby Prince Louis on July 9. The youngest of the Cambridge clan was baptized in a private ceremony with his parents Prince William and Kate Middleton proudly looking on as other attendees, like Prince Harry and Meghan Markle, beamed with delight. Click through our gallery to see every special moment and find out all the details from the milestone day!Fast asleep in his mother Kate's arms, Prince Louis was blissfully unaware of the excitement his appearance was causing across the world. The Duchess of Cambridge was all smiles outside the chapel as she held her third child. Photo: Dominic Lipinski - WPA Pool/Getty Images

Squad goals! Catherine was joined by her husband Prince William and their other two children Prince George and Princess Charlotte, who were their usual adorable-selves. The outing marked the first time the five-some appeared in public together.Photo: Dominic Lipinski - WPA Pool/Getty Images

The tiny Prince, who officially made his debut on April 23 when he was merely a few hours old, remained calm at the private affair. At eleven weeks old, Louis was christened in front of his godparents and loved ones. The Prince is the second to newest member of the royal family, after Meghan Markle officially became a Duchess upon her marriage to Prince Harry back in May. Louis is the Queen's eighth great-grandchild and is fifth-in-line to the throne, after Prince Charles, Prince William, Prince George and Princess Charlotte.Photo: Dominic Lipinski - WPA Pool/Getty Images

Beaming with pride, the Duchess made a luminescent appearance at her son's christening. She donned a radiant Alexander McQueen dress in a frothy cream color that matched her son's traditional gown. She was heard describing her sleeping boy as "very relaxed and peaceful". The Duchess added with a smile: "I hope he stays like this." In the blurred background, newlyweds Harry and Meghan can be seen looking delighted for their nephew.Photo: Dominic Lipinski - WPA Pool/Getty Images

Following in the footsteps of his older brother and sister, Prince Louis’ christening was conducted by the Archbishop of Canterbury, Justin Welby.Photo: Getty Images

The Duchess of Cambridge shared yet another sweet moment with her youngest child after the christening service, while Prince William walked closely behind clasping hands with their firstborn son George and daughter Charlotte.Photo: Getty Images

Princess Charlotte, who was dressed in a floral print dress and a blue bow headband, adorably departed the christening carrying a program tucked under her arm.Photo: Getty Images

The three-year-old was believe to be wearing a Pepa & Co. headband, which her little pair of Mary Jane's matched perfectly.Photo: Dominic Lipinski - WPA Pool/Getty Images)

Duchess Meghan looked gorgeous in an olive green Ralph Lauren midi dress, with her signature favorite bateau neckline and swept-back hairstyle. Meanwhile, Prince Harry looked dapper in a navy suit and bright tie.Photo: DOMINIC LIPINSKI/AFP/Getty Images

Proud grandparents Michael and Carole Middleton smiled at photographers as they arrived to their grandson’s baptism at the Chapel Royal. Kate’s parents were followed by Pippa and her husband James Matthews.Photo: Getty Images

Pippa Middleton looked classic and elegant, hiding her baby bump in a pale blue midi dress by Alessandra Rich. She complemented the pleated skirt dress look with a lovely hat. Her husband James Matthews happily walked beside her.Photo: DOMINIC LIPINSKI/AFP/Getty Images

James Middleton arrived to the service with one of Prince Louis’ godparents, Lady Laura Marsham, who is the wife of Prince William's close friend James Meade.Photo: Getty Images

Prince Charles and the Duchess of Cornwall led the royal pack, representing the older generation of royals as Queen Elizabeth and Prince Philip did not attend. Camilla wore an elegant cream dress by Fiona Clare, and a straw-colored hat by Locke. Photo: DOMINIC LIPINSKI/AFP/Getty Images

Crowds of royal well-wishers lined the streets outside of Chapel Royal at London's St. James's Palace.Photo: WENN

Ahead of the ceremony, the official royal family twitter shared some interesting tidbits about their christening traditions. In a surprising factoid, they revealed that "one of the three top tiers of The Duke and Duchess of Cambridge's eight-tier wedding cake will be used for the Christening cake." Photo: Twitter/@RoyalFamily

They also shared that Prince Louis wore a replica of the Royal Christening Robe which was made in 1841 for the christening of Queen Victoria's eldest daughter, Victoria, Princess Royal. "The gown was subsequently worn by Prince Louis' great-grandmother The Queen, grandfather The Prince of Wales and his father The Duke of Cambridge at their Christenings," they wrote.The new robe, worn by Louis, was created by the Queen's dresser Angela Kelly.Photo: Twitter/@RoyalFamily