Princess Charlotte messed up royally at Sunday’s star-studded coronation concert.

When newly-crowned King Charles III and Queen Camilla walked past the 9-year-old to take their seats in the royal box, she followed mom Kate Middleton’s example and dropped into a curtsy for her grandpa.

But while Middleton, curtsied again when her mother-in-law passed by, the young princess, who was wearing a Self-Portrait chiffon dress at the time, did not follow suit.

Camilla, did not appear fussed by her granddaughter’s error, patting a smiling Charlotte’s arm as she walked by.

Charlotte is usually attuned to royal protocol and has made headlines over the years for correcting her brothers’ behavior.

During Queen Elizabeth II’s Platinum Jubilee festivities in June 2022, the youngster stopped Prince Louis from excessive waving to onlookers watching their carriage ride.

That same week, Charlotte corrected Prince George’s posture while standing on the Buckingham Palace balcony.

Prince William poked fun at his daughter’s manners during the Big Lunch at Windsor Castle on Sunday, saying she had her hands full “making sure her little brother behaved himself” at Saturday’s coronation.

“She’s very tired after yesterday,” the Prince of Wales, 40, said, according to Hello! magazine. “She’s having a quiet day at home.”

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Charlotte did sit beside Louis, 5, during the hours-long service at Westminster Abbey — which he yawned his way through.

The duo even entered holding hands while walking behind Middleton, 41, and William.

The little ones were able to let loose Monday morning as they volunteered at 3rd Upton Scouts Hut in Slough for the Big Help Out holiday.

Not only did George, Charlotte and Louis toast marshmallows for s’mores and attempt archery, but they got their hands dirty with varnishing, shoveling and digging projects.