George, Charlotte and Louis have the sweetest nickname for King Charles

Prince George, Princess Charlotte and Prince Louis have an adorable nickname for King Charles — which also happens to be quite a regal one.

George, Charlotte and Louis have apparently always called Charles "Grandpa Wales," according to the Mirror. While the children's dad Prince William has now taken over the Prince of Wales title from his dad, that's what Charles was known as when the little ones were born. Seems like it stuck.

This tidbit has come out of the woodwork after King Charles and Queen Camilla each received a new nickname this week as part of the Chelsea Flower Show.

A group of children who created the "RHS No Adults Allowed Garden" for the show gave Charles the nickname "King of the Compost" and Camilla the nickname "Queen of the Bees." They even made them badges that proudly displayed the royal couple's new monikers.

As for George, 10, Charlotte, 9, and Louis, 6, they don't just dole out the nicknames — they're also very much on the receiving end of them, too.

George's in particular is pretty hilarious. Circa 2019, according to the Mirror, the little boy's classmates were calling him "PG," which are the initials of "Prince George." His parents Kate and William loved this nickname, but they took it a step further, calling him "Tips," as in "PG Tips." Apparently, George's school friends and family members still call him this to date.

Charlotte has two sweet nicknames that we know of, per the Express, with one being on the more traditional side: Lottie. The second, however, is definitely more out of left field. In 2019, William called his daughter the French word "Mignonette" at the Chelsea Flower Show — which roughly translates as "cutie" or "sweet one."

The Express also previously reported that Prince Louis is known by close family members as "Lou Lou." Aww!

Meanwhile, the Wales children alternately call their dad "Pops" or "Papa," but have also been known to jokingly refer to him as "Poachy" in reference to a radio show they once listened to on the way to school. Go figure!