The two siblings’ birthdays are just over a week apart – with 3-year-old Charlotte celebrating hers on May 2.
Louis was born on April 23 – so it makes sense that both Christmas portraits were likely taken when they were around the same age.
The bond between Louis and Charlotte was apparent from early on, when proud parents Prince William and Princess Kate shared new photos of the siblings to mark the birth of the royal baby and to celebrate his big sister’s third birthday in May.
The adorable photo of the duo was taken on May 2 (Charlotte’s birthday).
Already a protective big sister, Charlotte cradles Louis in her lap and places a sweet kiss on her sleeping baby brother’s head.
Charlotte’s love for her younger brother was on display again in portraits from Louis’ christening.
In a group shot with all the royal family members, including uncle Prince Harry and aunt Meghan Markle, Charlotte sits next to her mum.
While everyone else looks at the camera and smiles, the proud big sister is focused only on Louis as she lovingly gazes at her baby brother and adorably holds his hand.