Millions of people watching around the world will be invited to make a pledge of allegiance to Charles when he is crowned King this weekend in London - including New Zealanders.
It's one of a slew of changes to the ancient ceremony.
But at a time when the monarchy's popularity is at a record low, the idea of a people's pledge has been greeted by a chorus of criticism.
Although there are some royal super fans, like John Loughrey, who don't even need to be asked to take the pledge. He's already camping out ahead of this weekend's coronation to get a front-row seat to history.
"We've been told we're the first. We're doing this for King and country," he said.
While Loughrey is a living, breathing, walking pledge of allegiance to the King, come this Saturday, the Royal Family is hoping he'll be joined by millions around the world.
In 1953, the coronation was televised for the first time and Queen Elizabeth II took her oath to serve in front of more than 27 million viewers.
But in 2023 there'll be a new first. Instead of just watching King Charles take his solemn vow, the public will be asked to take one too.
So get your vocal cords ready and repeat after the Archbishop of Canterbury: "I swear that I will pay true allegiance to Your Majesty, and to your heirs and successors according to law. So help me God."
It's one of several big changes to the ancient ceremony. Female clergy will also be involved for the first time, as well as religious leaders from all faiths in a bid to celebrate unity.
But as the coronation approaches and the rehearsals ramp up, monarchy popularity has hit a record low - only three in every 10 Brits consider the monarch "very important".
So while the call for millions to pledge their allegiance could well elicit a chorus of swearing come Saturday, it might not quite be the kind the King has in mind.
