Per tradition, the photo was taken by Louis' mom, Kate. This year's snapshot shows Louis at Kensington Palace shortly before the little one left for his first day of nursery at the Willcocks Nursery School on Wednesday.
Louis proudly sports his backpack in the photo, and appears ready to go on his little red bike.
Three tomorrow! 🚲
Taken earlier this week by The Duchess before he left for his first day of nursery, The Duke and Duchess are pleased to share a new image of Prince Louis. 🎈 pic.twitter.com/AGgfLI39tW
Louis' birthday comes just two days after his great-grandmother, Queen Elizabeth II, turned 95. The queen spent her milestone birthday at Windsor Castle, as she continues to mourn the death of her husband, Prince Philip.
It was at Philip's funeral that Kate played "peacemaker" between her husband, Prince William, and his brother, Prince Harry. See more in the video below.