The King would find the idea of people paying homage to him during his Coronation “abhorrent”, the broadcaster Jonathan Dimbleby believes.
For the first time, the public are being given an active role in the ceremony as they are invited to swear allegiance to the King.
But Dimbleby, a close friend of the King, told BBC R4’s Today programme he has “never wanted to be revered”.
The Archbishop of Canterbury has previously said the oath is voluntary.
Justin Welby said earlier this week there was “no drama” about whether the public swear allegiance to the monarch, reiterating that this was “an invitation; it’s not a command”.
The “homage of the people” is a new addition to the ancient ceremony which is being led by the archbishop.
It was revealed, along with other details of the service, in a liturgy published by Lambeth Palace last weekend. Lambeth Palace said the liturgy had been produced “in close consultation” with the King and the government.
A spokesperson for Lambeth Palace said it hoped people would say the homage out loud and there would be a “sense of a great cry around the nation and around the world of support for the King”.
Campaign group Republic called the idea “nonsense” and “offensive”.
Dimbleby, who is attending the Coronation on Saturday, said he feels there may have been a miscommunication because it is “so different from the king that I know”.
Asked what the King thinks of the idea, he told the Today programme that he did not know “for certain”, but added: “I can think of nothing that he would find more abhorrent.
“He’s never wanted to be revered. He’s never wanted, so far as I know, to have anyone pay homage to him except in mock terms as a joke.
“He wants, I think, to feel that people will share in the event.”
Dimbleby said it seemed to him to be an initiative by the archbishop “who thought it would be a good thing to give everyone a chance to pay that homage”.
He said: “I think it was well intentioned and rather ill-advised, because its effect, of course, is to allow everyone to say, well, I’m not going to pay homage.”
He added that it is “so different from the King that I know to ask for homage or to expect homage”.
It is unclear who came up with the idea, but it is “pretty inconceivable” that Buckingham Palace was not aware of the homage element or the entire order of service before it was announced, the BBC’s Religion Editor Aleem Maqbool told the Today programme.
Earlier this week, the archbishop said it was fine if people did not want to join in the voluntary oath.
Asked about some newspaper reports suggesting he had gone “rogue”, he insisted the service had been a “huge, collaborative [with Buckingham Palace and the Cabinet Office] and very lovely process”.
“There’s no individual who can claim the credit for this service,” he added.
While reading out the oath, the archbishop will call upon “all persons of goodwill in the United Kingdom of Great Britain and Northern Ireland, and of the other realms and the territories to make their homage, in heart and voice, to their undoubted King, defender of all”.
The order of service will read: “All who so desire, in the abbey, and elsewhere, say together:
“I swear that I will pay true allegiance to Your Majesty, and to your heirs and successors, according to law. So help me God.”
With less than 24 hours until the Coronation gets under way, the King and Camilla, the Queen Consort, were seen arriving at Westminster Abbey for a final rehearsal.
King Charles waved from the car window as he arrived.
The royal couple have recorded an announcement reminding train passengers to “mind the gap” – which will be played at every railway station across the UK and all London Underground stations between Friday and Monday.
King Charles tells passengers: “My wife and I wish you and your families a wonderful coronation weekend.”
Camilla then says: “Wherever you are travelling, we hope you have a safe and pleasant journey.”
He was later pictured looking happy and relaxed at a lunch for realm prime ministers and governors general at Buckingham Palace.
Saturday’s historic occasion will include a procession, ceremony involving regalia – symbols of royalty such as the crown, orb and sceptres – and another procession back to Buckingham Palace, where there will be a balcony appearance from the monarch and a fly-past.
More than 400,000 people will receive a medal recognising their contribution to the Coronation.
Made of nickel silver, it has the royal cypher on one side and images of the King and Queen Consort on the other.
Recipients will include police, ambulance workers, choristers and military personnel.