Cape Town - How adorable! Prince William’s nickname for Princess Charlotte is the sweetest thing we’ve heard all day.
The cute moment occurred during the royal family’s tour of the Chelsea Flower Show in London, where the Duchess of Cambridge displayed her specially designed garden, the Express reports.
In a clip shared by Kensington Palace, William can be seen playing with his three children, Prince George (5), Princess Charlotte (4) and Prince Louis (13 months).
The Duke of Cambridge can be heard asking his oldest son George to rate Kate’s garden.
"What would you give it out of 10? How many marks out of 10 would you give it – 10 being the highest?" he asked the young royal.
"Twenty!" George replied.
But royal fans quickly spotted William saying something to Charlotte that sent the internet into a frenzy, People reports.
William reportedly called Charlotte "Mignonette," a derivative of the French word "mignon", when asking her to give him a push on the rope swing.
In English terms the endearing term means cute, dainty or darling, Fox News reports.
"Anyone notice right before he asked Charlotte to push him, he called her by a lovely nickname… William called her 'Mignonette' which means ‘delicate,'” a social media user suggested.
“I think it’s 'Mignonette'… if that’s true how sweet is that??” another user said.
Kate’s "back to nature"-themed garden, which was co-designed with award-winning landscape architects Andrée Davies and Adam White, was reportedly created to highlight the importance of kids playing outdoors.
WATCH THAT VIDEO HERE: