Documentary shows King and Queen relaxed and joking during coronation rehearsals

Charles quips “I can fly” as he holds up his lavish robes like wings during a practice run in Buckingham Palace, while Camilla says deadpan “here we are with all the lads” as her pages hold up the train of her dress.

Annabel Elliot, the Queen’s younger sister, is interviewed for the 90-minute documentary – Charles III: The Coronation Year – and describes how it was “surreal” watching Camilla and the King carried off in the Gold State Coach after their crowning.

In a clip released ahead of the film’s screening on Boxing Day, Prince George is featured during the palace rehearsal, and in a new photograph the Prince of Wales is shown laughing with Charles as William practices fitting lavish robes around the King for the ceremony.

Charles is shown laughing and shaking his head when the Archbishop of Canterbury Justin Welby forgets the words to part of the liturgy – the prayers and actions of the coronation service – in a second rehearsal clip filmed at Westminster Abbey.

Archbishop Welby, who led the coronation ceremony, confesses to the camera in an interview: “I have a memory that is probably about as good as our spaniel’s – in other words, zero.”

Mrs Elliot says about the historic crowning: “And I thought back, of being, you know, two-years-old and watching the Queen’s coronation on a tiny black and white television and there goes this golden coach with my sister in it.

“I can’t explain the feeling because it’s so surreal and this cannot be happening – yeah it was quite a moment.”

Charles and Camilla’s close friend Fiona the Marchioness of Lansdowne, tells the BBC documentary the moment when she, Mrs Elliot and the Queen saw each other in their coronation gowns for the first time was like the “bridesmaids going to see the bride”.

The documentary chronicles some of the major moments from the first year of the King’s reign, and includes an interview with the Princess Royal who gives her recollections of those first 12 months and how the monarch and his wife have adapted to their new roles.

In the Buckingham Palace clip, Charles and his wife are shown rehearsing their route through Buckingham Palace with their pages of honour.

Camilla’s train is held by her four pages – her three grandsons, twin boys Gus and Louis by her daughter Laura Lopes, and 13-year-old Frederick, by son Tom Parker Bowles, and her great-nephew, Arthur Elliot, 10, Mrs Elliot’s grandson.

When Major Oliver Plunket, the Queen’s equerry says “Just be careful of Her Majesty’s dress”, Camilla asks her pages “You won’t tread on my dress?” and a little later as the schoolboys hold up her train she says “Here we are with all the lads”.

The King’s pages holding up his gown are grandson Prince George, Nicholas Barclay, grandson of Sarah Troughton one of the Queen’s Companions, Lord Oliver Cholmondeley, son of the Marquess of Cholmondeley also known as film-maker David Rocksavage and a friend of the Prince of Wales, and Ralph Tollemache.

Camilla’s younger sister Mrs Elliot and the Queen’s friend Lady Lansdowne both had the formal role of Lady in Attendance during the coronation.

Mrs Elliot appears emotional in footage as she and members of the coronation entourage wave off Charles and Camilla as they practise leaving Buckingham Palace for the coronation staged at Westminster Abbey on May 6.

Lady Lansdowne says in an interview: “There was just a really exciting moment of just getting them into that carriage the first time, and we knew we were off.

“We were ready, we were ready and we were ready to go out and face literally the world.”

Charles III: The Coronation Year will be screened on December 26 at 6.50pm on BBC One and iPlayer.