STOP IT.

Prince Louis is only 18 days old (he arrived into the world on April 23 FYI) but already, he's very popular with his big sister Charlotte. Although it can be difficult for older siblings when a new arrival joins the family, it seems that Princess Charlotte has taken to her role of big sister like a duck to water.

The Duke and Duchess of Cambridge are very pleased to share two photographs of Princess Charlotte and Prince Louis, taken by The Duchess at Kensington Palace.

This image was taken on 2nd May, on Princess Charlotte’s third Birthday. pic.twitter.com/H5VVgIwRGp — Kensington Palace (@KensingtonRoyal) May 5, 2018

According to Us! Weekly, the little girl is mad about her younger brother and won't leave his side. A source told the publication that the two royals have "a great bond". The insider said that Princess Charlotte is just like her older brother, Prince George, and now Charlotte is getting on great with her younger brother, just like George did with her.

"Charlotte is just like him. They have a great bond, and a similar connection is growing between Charlotte and Louis."

This image of Prince Louis was taken by The Duchess of Cambridge at Kensington Palace on 26th April.

The Duke and Duchess would like to thank members of the public for their kind messages following the birth of Prince Louis, and for Princess Charlotte’s third birthday. pic.twitter.com/bjxhZhvbXN — Kensington Palace (@KensingtonRoyal) May 5, 2018

There was also this sweet moment between the young prince and princess on the way to see their younger brother at the Lindo Wing in St Mary's Hospital, just after his birth. Here's hoping we get to see lots more adorable photos of the three royal siblings, rumour has it that Prince George and Princess Charlotte will take on the roles of page boy and bridesmaid at the wedding of their uncle, Prince Harry, and his wife-to-be, Meghan Markle, next weekend (19 May),