Prince William, Kate Middleton celebrates son Louis special day

​Prince William and Kate Middleton are celebrating their youngest son, Prince Louis, another trip around the sun.

​The Prince and Princes of Wales took to their official Instagram account on Thursday, April 23, to mark Louis's 8th birthday along with a sweet tribute.

​In the celebratory post, the proud parents posted the birthday boy's recent snap, looking all grown up.

​Expressing love for Louis, William and Kate captioned the post, "Happy birthday, Louis! 8 today!"

​In the snap, Louis can be seen beaming smiles as he wrapped his arms on his chest while wearing a blue sweater over a same color shirt.

​The picture appeared to be taken at a beachy outing on a chilly day.

​It is pertinent to mention that William and Kate are also parents to daughter Princess Charlotte, 10 and eldest son Prince George, 12.

​This came after Kate and William took a step back from the public eye earlier in April to spend time with their children to spend some quality time with them during school break.

​Speaking to Fox News Digital, royal expert Ian Pelham Turner said, "William and Kate have traditionally taken time off during their children’s school holidays to try to normalize their upbringing as much as they can."

​The expert further said, "There has obviously been a lot of strain on the children’s lives due to Kate’s past cancer diagnosis. And like everyday parents, they wish to create as many positive and happy memories for the family to cherish."