"Sharing some festive memories this Christmas because #ShapingUs is all about the vital importance of our early years and the role played by those around us in shaping the rest of our lives," Kensington Royal wrote in a tweet. "The Princess, Christmas 1983."
Kate can be seen enjoying what appears to be a holiday meal as a toddler.
"Prince Louis is definitely his mummy 2.0," one Twitter user wrote. "What an adorable picture!! Prince Louis is you in this one," another added.
Louis has been a fan-favorite for years, and the little one's demenour reminded one royal expert of his paternal grandmother, Princess Diana. OK! previously reported American royal expert Kinsey Schofield was excited to see Louis in the Wales Christmas card.
Schofield gushed over the little one's personality in the social media greeting.
“He's so full of sass. He is just so precious and he is just a lightning bug when it comes to this family," she stated.
William and Kate are often praised for their ability to balance royal duties and raising their three children.
“Just watching them all together, you can tell that their parents are very hands-on. They're absolutely adored, they're well-behaved," Schofield explained. “You know those little moments that we actually see Louis’s personality. He is the sweetest little boy, but you can tell he's a little Spitfire."
Prior to Schofield's television appearance, Kate volunteered with Louis, Princess Charlotte and Prince George at a baby bank.
“Here there’s lots of people who give up their time and there are lots of volunteers who come and help,” Kate told the trio as they grabbed gifts out of their car. “And so you’re the volunteers for this evening.”
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Kate dedicated her time as a working royal to helping Britain's youngest citizens, and the princess discussed the importance of being a kid.
"Our experiences, relationships and surroundings during early childhood lay foundations that shape the rest of our lives, and future society," she shared on Instagram. "Supporting parents and carers, who are doing their best to provide for their families in challenging circumstances is essential and can have a life-changing impact."