The Cambridges are complete for Prince Louis' christening.

On Monday, Prince William and Kate Middleton arrived at the Chapel Royal in St. James's Palace in London. The Duke and Duchess of Cambridge stepped out for the event with their two-month-old son and his siblings, Prince George, 4, and Prince Charlotte, 3. It was the first time the family of five was spotted together, People reported.

Middleton wore another Alexander McQueen dress for her son's christening. The mother of three paired her cream suit with a headpiece from Jane Taylor.

The Cambridges arrived with Prince Louis in Middleton's arms. On the other hand, Prince William held Prince George and Princess Charlotte's hands. Prince Harry and Meghan Markle were behind them.

The Duke and Duchess of Cambridge chose two hymns for the ceremony - "O Jesus, I have Promised" and "Lord of All Hopefulness." For the anthems, the couple opted for "This is the day which the Lord hath made" by John Rutter and "Suo Gân," a traditional Welsh Lullaby by Gareth Wilson. Both songs were performed by The Choir of Her Majesty's Chapel Royal.

The first anthem, "This is the day which the Lord hath made" was composed for Prince William and Middleton's royal wedding in 2011. Meanwhile, the processional organ music would be R. Vaughan William's Prelude on Rhosymedre, which was also played at their wedding and at Prince Charles and Princess Diana's nuptials.

Also spotted at the event were Middleton's parents, Carole and Michael. The duchess' sister, Pippa, arrived with husband James Matthews. Pippa is expecting her first child this fall.

Royal expert James Brookes said earlier that Prince William and Middleton would make a compromise at Prince Louis' christening. Both will share photos but will still make the event private.

"Judging by the previous christenings, and the importance of the day for the family, Louis’ christening will be a private affair, perhaps no surprise there," Brookes told Express. "These photos, and the images of the family arriving, will be seen as a compromise by the Cambridges. They give the photographers something to work with and then they expect a bit of privacy for the rest of the day."

Middleton had a fast recovery after Prince Louis' birth. In fact, just seven hours after delivery she stepped out looking pristine for her newborn's public debut.

The Cambridges
Prince William and Kate Middleton seen for the first time with three kids, Prince George, Princess Charlotte and Princess Louis. Pictured: Princess Charlotte, Prince William, Prince George and MIddleton as they arrive at the Chapel Royal, St James's Palace, London for Prince Louis' christening on July 09, 2018 in London. Getty Images/Dominic Lipinski