The sweet nickname Prince William calls his daughter, Princess Charlotte

While Prince George’s alleged nickname may have secretly given away the name of Meghan Markle and Prince Harry’s baby, Princess Charlotte's nickname is actually quite French.

While attending the Chelsea Flower Show to see Kate Middleton’s latest project, the Duke and Duchess of Cambridge brought along their children Prince George, 5, Princess Charlotte, 4, and Prince Louis, 1. The duchess created a garden complete with a rope swing and tree house in order to demonstrate the mental health benefits of nature, which of course, her children seemed to enjoy playing in.

In a video shared by Kensington Palace on Twitter, Prince William asks George to rank his mother's garden on a scale of one to 10. Playing with the swing, he answers, "20."

"Twenty out of 10? That's pretty good. I think mummy's done well," William replies.

Later, the Duke of Cambridge calls over Charlotte to give him a push on the swing. Only he doesn't call her by her name, he calls her "Mignonette."

The name Mignonette is a common French term of endearment and can be translated to "favorite or little darling." The word is also derived from "mignon," meaning small, cute, sweet or delicate.

Seriously, how cute is that?!

The Cambridge family reportedly played in the garden for about an hour, but not without Prince Louis completely stealing the show.