Prince Charles has said for the first time that his wife Camilla "could be" the Queen when he takes the throne.
Asked in an interview on US channel NBC whether the Duchess of Cornwall could ever become Queen Consort, he initially stumbled over his answer.
He then added: "We'll see won't we? That could be."
Clarence House said that "nothing had changed" since the couple's wedding, and that the Duchess would become Princess Consort as was stated then.
BBC royal correspondent Nicholas Witchell said the issue was the title which Camilla would take when the prince became king, not her role.
According to 1,000 years of history and precedent the wife of a king becomes a queen, as a Queen Consort, which has no constitutional power.
But at the time of their marriage five years ago, it was announced that Camilla would assume the Princess Consort title when Charles became King.
That came at a time when there were several newspaper polls indicating a lack of public support for Camilla ever being known as Queen Camilla.
Our correspondent said Prince Charles had been caught unawares in the interview and had given a rather stumbling answer, but he could have "stuck to the script" of Clarence House.
Instead he gave that answer, which confirmed what people suspected, that he wanted Camilla crowned alongside him as Queen Consort, which was revealing, our correspondent added.
The interview was conducted in the grounds of the Castle of Mey in Scotland, in August - before media attention focused on his eldest son Prince William's engagement to Kate Middleton.
However, when asked how his heir should cope with the glare of publicity, Charles admitted it was not easy to cope with "constant lecturing".
"Don't take the advice of the media, is my advice," he said.
"It's very intrusive indeed and very difficult. I feel for him deeply because in my day it was difficult enough."
Asked about his role in public life, the Prince said: "The trouble is, there isn't a job description so you have to rather make it up as you go along, which doesn't always appeal to everybody else.
"You pick it up as you go along, from a very young age, and it gradually dawns on you what it's actually all about."
Charles said he preferred not to think about becoming King, given that it would come as a result of the death of his mother.
"If it comes then you have to deal with it," he added.
The Prince was also asked about his sons' military careers.
William, 28, and now an RAF search and rescue helicopter pilot, was a former Army officer. His 26-year-old brother is also an Army officer being trained to fly Apache helicopters.
Charles, 62, said he sympathised with William for not being allowed to be deployed to Afghanistan, while Harry returned from a tour in the combat zone in 2008.
"It was very difficult for William, my eldest, not to go. But I did say to him 'You know, look, when I was in the Navy for five years, in the early 1970s, I had the same problem, they wouldn't send me anywhere'."
Harry had been "terribly keen" to serve in Afghanistan, Charles said, adding: "When Harry was out there, I worried the whole damn time."
The interview was held to mark the screening on NBC of a documentary that explores the themes of Charles's new book, Harmony, which examines ways of living sustainably.