Prince Louis Looks So Grown Up In Adorable New Pic Celebrating His 3rd Birthday

The littlest of the Cambridge kids isn't so little anymore.

Prince Louis, the third child of Prince William and Kate Middleton, is celebrating his third birthday on April 23. The couple shared a new photo of Louis, and he's simply adorable.

That wasn't the only thing the family had to celebrate. This week, the little guy took his first big steps into the world of education. He started school at The Willcocks Nursery School, where his older sister Princess Charlotte also attended.

The bit of good news comes as the family continues to mourn the loss of Prince Philip. Though the Cambridge children were understandably not among those present for the intimate funeral of the late Duke of Edinburgh earlier this month, they've talked about his death with their parents.

Happy birthday, Prince Louis! The youngest of the three Cambridge kids turns 3 on April 23. To celebrate, the couple released a new photo of Louis, along with some exciting news.

"Wishing Prince Louis a very happy third birthday today. ," the caption reads.

"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. ."

Prince Louis started school this week at a place familiar to Prince William and Kate Middleton. He's attending The Willcocks Nursery School, the same school that Princess Charlotte attended to begin her education. Both Charlotte and Prince George now attend Thomas's Battersea.

"They chose that nursery because they thought it would be an ideal first step for Charlotte's education, and they were impressed by the team who work there," a source told People.

The late start is likely due to different health regulations surrounding the health crisis in the UK. Still, it's significant for the family, as it's the first time all three kids are out of the house.

At 7, 5, and 3, the Cambridge kids are growing up fast. Still, it was determined they were too young to attend Prince Philip's funeral last weekend. Sources close to the family say that William and Kate have talked to the kids about their great-grandfather's death.

"William told George, Charlotte and Louis that Prince Philip has 'gone to heaven' and 'is an angel now,'" a source told Us Weekly.

"They're still so young so he and Kate wanted to let them down gently."

"Naturally, the children are very upset, particularly George and Charlotte," the source continued.

"Louis is still very young and had only met Prince Philip a couple of times. George, Charlotte and Louis helped William choose a photograph of Prince Philip to hang in their home in memory of him."

In a statement shared on social media, Prince William reflected on what it meant to him that his wife and children were able to have relationships with Philip.

"I will always be grateful that my wife had so many years to get to know my grandfather and for the kindness he showed her. I will never take for granted the special memories my children will always have of their great-grandpa coming to collect them in his carriage and seeing for themselves his infectious sense of adventure as well as his mischievous sense of humour!" he wrote.

"My grandfather was an extraordinary man and part of an extraordinary generation. Catherine and I will continue to do what he would have wanted and will support The Queen in the years ahead. I will miss my Grandpa, but I know he would want us to get on with the job."