“The big one that you’re crowned with, the St Edward’s Crown, it weighs five pounds (more than 2kg),” Charles said in Coronation Girls.

“It is much heavier and taller, so there’s always that feeling of feeling slightly anxious, in case it wobbles,” the king added, speaking of the 17th-century gold headpiece in which he was crowned last year after the death of his mother, Queen Elizabeth II.

Coronation Girls tracks the journey of 12 women from Canada who sailed across the Atlantic to London for Elizabeth’s coronation in 1953.

The women retraced their steps to Buckingham Palace in 2023, where they were surprised by the king, who said he “remember(ed) quite a lot” from his mother’s coronation despite being only four years old.

“I remember it all so well then, because I remember my sister and I had bath time in the evening,” Charles said.

“My mama used to come up at bath time wearing the crown to practice. You have to get used to how heavy it is.”

Directed by Canadian filmmaker Douglas Arrowsmith, Coronation Girls will be aired on Boxing Day in Canada.

The documentary will be released internationally next year.