Lively Prince Louis must break with his own little tradition for his grandfather's Coronation, one royal expert claimed.
With the finishing touches being put on the ceremony, many are wondering whether the four-year-old will continue wearing shorts everywhere he goes.
Louis is rarely seen in trousers - even during winter months - and royal fans love the energetic lad's commitment to his trademark look, despite the cold.
But with the momentous day creeping closer, former BBC Royal Correspondent Jennie Bond said it was high time he smartened up his act!
She told OK! Magazine that Louis - who turns five on Sunday - needs to get shot of the shorts next month.
"I think it's time he wore trousers, especially at the Coronation," she said.
"Anything else would look odd and far too informal. I'd like to see him in a little suit at the age of five, he'd look really cute in a little suit.
"And I'm sure Charlotte will be wearing something very feminine and very lovely.
"When it comes down to it, Louis should be wearing long trousers and Charlotte will be wearing a stylish young lady's dress, it would be the best solution."
According to etiquette expert William Hanson, the reason behind Prince William and Kate Middleton's outfit choices for their sons is derived from upper-class tradition.
Speaking to Harper's Bazaar, he explained that the tradition dated back to the 16th century, saying: "It's a very English thing to dress a young boy in shorts. Trousers are for older boys and men, whereas shorts on young boys is one of those silent class markers that we have in England.
"Although times are slowly changing, a pair of trousers on a young boy is considered quite middle class – quite suburban. And no self-respecting aristo or royal would want to be considered suburban. Even the [Princess of Wales]."
Prince George and Prince Louis aren't the first royal youngsters to follow the tradition as both Prince William and Prince Harry were also dressed in shorts for their public appearances when they were small.
But according to royal expert Ingrid Seward, it could be that Charles has relaxed a strict rule on dining that his late mother used to insist on - and it would have affected Prince George, Princess Charlotte, and Prince Louis.
The royal biographer and editor-in-chief of Majesty Magazine told The Sun: "They will all have dinner together but not the young children they will eat in the nursery dining room.
"The Queen always said until they could hold a knife and fork properly they could not eat at the table, but Charles might have relaxed that rule a bit. But dinner is only for grown-ups."