ICYMI: Princess Charlotte made a cheeky comment to paparazzi at Prince Louis' christening.

At only 11 weeks old, Prince Louis has made his second public appearance in the arms of his mum, the Duchess of Cambridge, at his christening.

The ceremony took place at The Chapel Royal at St James’s Palace in London, and in attendance was Prince Charles, Duchess Camilla, Prince Harry and Meghan Markle, as well as Duchess Catherine’s family – parents Carole Middleton and Michael Middleton, and siblings James and Pippa.

While all eyes were on the newborn prince on his big day, Prince Louis’ big sister Princess Charlotte briefly became the centre of attention when she had some rather cheeky words for the photographers outside the chapel.

As she walked past them with her family, she told them: "You can't come in", before eyeing them off suspiciously until she is out of sight.

The video of the adorable moment was posted to the World of Royals Instagram early this morning and shows that Princess Charlotte is taking her duties as a protective big sister very seriously.

The Prince of Wales, The Duchess of Cornwall, The Duke and Duchess of Sussex, and The Cambridge departed from the Chapel Royal to Clarence House after the christening of Prince Louis. It's nice to see the family looking happy and radiant on this happy occasion. The Duchess of Cornwall joked with The Duchess of Sussex about the 'unusual hot' weather in London today. Can't you hear Princess Charlotte's sweet little voice at the end of this video? _______________________________________________ #PrinceCharles#PrinceOfWales#DuchessOfCornwall#PrinceHarry#MeghanMarkle#DukeOfUssex#DuchessOfSussex#PrinceWilliam#DukeOfCambridge#DuchessOfCambridge#PrinceGeorgeOfCambridge#PrinceGeorge#PrincessCharlotteOfCambridge#PrincessCharlotte#PrinceLouisOfCambridge#PrinceLouis#KateMiddleton#RoyalFamily#Royal#BritishMonarchy#BritishRoyalFamily#TagsForLikes#TagsForLikesApp#GainFollowers

A post shared by since 23-09-2015❤ (@worldofroyals) on Jul 9, 2018 at 10:24am PDT

While most of the British royal family were in attendance at the wedding, there was one very important person missing - the Queen.

The Queen and the Duke of Edinburgh had decided not to attend their great-grandson’s christening. A decision that Buckingham Palace says was made some time ago and agreed to by Prince William and Kate.

The 92-year-old monarch has a busy week ahead, marked by a visit from US President Donald Trump in Windsor on Friday. The Duke of Edinburgh, 97, has retired from public duties and has been enjoying his free time away from London.