LONDON - King Charles thanked singers who performed at a coronation concert in his honour at Windsor Castle for a "great treat" as a long holiday weekend of celebrations drew to a close on Monday.

Amid pomp and pageantry, Charles and his wife Camilla were crowned at London's Westminster Abbey on Saturday in Britain's biggest ceremonial event in 70 years.

Celebrations on Sunday culminated in the "Coronation Concert" featuring singers including Lionel Richie and Katy Perry, as the royals joined a 20,000-person audience at Windsor, the king's palace to the west of London.

In a surprise comedy sketch after the concert, Charles and Camilla interrupted Richie and Perry as they were relaying their experience of the weekend on TV show American Idol, on which the singers are judges.

Charles asked Richie whether the singers will be there "all night long", in reference to one of Richie's hits.

"I just wanted to check how long you'll be using this room for?" asked a chuckling Charles.

"Thank you so much for your brilliant performance, and Katy, it was wonderful, it really was. A great treat to have you both here."

DAZZLING SPECTACLE

After weekend of street parties and celebrations, Monday, which is a public holiday in Britain for the coronation, sees thousands of organisations get together for a volunteering programme.

Charles' son William and his wife Kate took part in "The Big Help Out" by visiting a scout group in Slough, near Windsor, with their children. Kate is president of the Scout Association.

It was the first royal engagement for their younger son Louis, 5, who pushed a wheelbarrow, played with a toy bow and arrow and ate marshmallows cooked on a fire.

Other members of the royal family volunteered at events around the country, as did Prime Minister Rishi Sunak and leader of the opposition Labour Party Keir Starmer.

"On the weekend, I think no other country in the world could put on such a dazzling spectacle," Sunak told broadcasters on his visit to a lunch club just outside London, where he met diners and chopped parsnips and strawberries.

"It was deeply moving to be in the coronation service and incredibly uplifting, and it's an experience I think that nobody will forget for the rest of their lives."

(Reporting by Alistair Smout; Editing by Alison Williams and Nick Macfie)