Queen Elizabeth II told her grandson Prince William to rip up the guest list he was given for his wedding and do it again himself to include his friends, he said in an interview.
The Duke of Cambridge also said he got got just half an hour's sleep before last year's wedding to Catherine Middleton, which was watched by billions around the world.
In extracts released Tuesday from a forthcoming ITV television documentary to mark the queen's jubilee, William said he went to his grandmother with his concerns about the guest list drawn up by royal officials.
"There was very much a subdued moment when I was handed a list with 777 names on -- not one person I knew or Catherine knew," he said.
"I went to her (the Queen) and said, 'Listen, I've got this list, not one person I know -- what do I do?' and she went, 'Get rid of it. Start from your friends and then we'll add those we need to in due course. It's your day'."
The April 29 wedding at Westminster Abbey in London was attended by around 2,000 people and more than one million people lined the processional route to see the happy couple.
William, the second in line to the throne after his father Prince Charles, admitted that his grandmother was a tough act to follow.
"There's not much wriggle room left for me to try and find my own path but I will do," said the search-and-rescue helicopter pilot in the extracts published in the Radio Times magazine.
"It's just a matter of learning what's gone before me. She's an incredible role model. I would like to take all of her experiences, all of her knowledge and put it in a small box and to be able to constantly refer to it."
The 29-year-old said he was much closer to his grandmother now than he was as a child.
"We're definitely a lot closer than we used to be," he said.
"Being a small boy it's very daunting seeing the Queen around and not really quite knowing what to talk about."
AFP, photo-Nimony