Queen Camilla's sister weeps as she watches key moment for royals unfold

The Queen’s sister was overcome as emotion as she watched Queen Camilla and King Charles on Coronation Day. Queen Camilla’s sister Annabel Elliot was tearful as she see them head to Westminster Abbey for the big moment.

The moving footage features in a behind-the-scenes look, released by the BBC for a documentary about the King’s first year as monarch, airing on Boxing Day.

She says in the documentary: “When I thought back to being two years old and watching the Queen’s Coronation on a tiny little 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.

“This cannot be happening. It was quite a moment.” The documentary also revealed lighthearted moments during King Charles’s coronation.

A trailer for the BBC documentary Charles III: The Coronation Year shows Archbishop Justin Welby getting mixed up with his lines while rehearsing a blessing with the King.

The King is shown laughing and shaking his head when the Archbishop forgets the words to part of the liturgy at the Westminster Abbey coronation service.

In an interview the Archbishop said: “I have a memory that is probably about as good as our spaniel’s – in other words, zero.” He is shown reading out the prayers to the monarch – but he stops, consults his notes and says “This can’t be right.”

An onlooker quips “you must have said this before” and King Charles turns red with laughter. The Archbishop later said to the camera: “He gave me a nice smile, nodded his head, but that was a glitch.”

Other funny parts of the documentary include footage of the King and Queen joking and laughing during coronation dress rehearsals.

King Charles says “I can fly” as he holds up his long robes like wings during a Buckingham Palace practice run.

Camilla’s train is held by her four pages – and as the schoolboys hold up her train she says: “Here we are with all the lads.”

Charles III: The Coronation Year will be shown on Boxing day at 6.50pm on BBC One and iPlayer.