The King has recalled how his late mother would wear her heavy Imperial State Crown to bath him and his sister, Princess Anne, at night as she practiced for her coronation in 1953.

And he admits to feeling ‘slightly anxious’ about the weight of his own and whether it would ‘wobble’ as he walked through Westminster Abbey last year.

The candid memories came as he met a group of remarkable Canadian women who were hand-picked to attend the crowning of Queen Elizabeth.

Last year 12 of them came back to the UK to retrace their steps – despite their average age now being 89 – and were shocked when they were invited to Buckingham Palace, with Charles making a surprise appearance.

A poignant new film, Coronation Girls, follows their story from the 1950s to the present day and how the experience shaped some of their lives forever.

In the summer of 1953, 50 young women from across Canada were sponsored by Canadian businessman and philanthropist Garfield Weston to travel to the UK.

The group, who were around 17 years in age and in many cases had not even left their home home towns before, sailed across the Atlantic on the Empress of France to reach Liverpool, where they boarded a train down to London for the historic event.

The women describe their trip as ‘life-changing’ and ‘magical’, vividly recalling the moment the new Queen passed them in the gold state coach during procession.

Queen Elizabeth II was crowned in Westminster Abbey in June 1952 

The King told the women his grandmother, the Queen Mother, told him what was happening during the Coronation ceremony (pictured: The Queen Mother, Prince Charles and Princess Margaret watch the Queen being Crowned)

The candid memories came as he met a group of remarkable Canadian women who were hand-picked to attend the crowning of Queen Elizabeth

‘The crowds were so joyous and so loud they drowned out the marching bands,’ said one.

At the time the late Queen was around nine years older than the girls, which, some said, helped them feel a special connection with the new monarch.

Of the 50 women that first came to the UK, 16 have since died.

In June 2022, the remaining group wrote a letter to the then 96-year-old Queen asking if they could have tea with her when they came to the UK. Sadly she died four months later, before their dream could ever be realised.

But the trip still went ahead in December 2023, when they met her son, now King.

In the 90-minute documentary, King Charles tells the women he could remember ‘quite a lot’ of his mother’s coronation, despite being just four years old at the time.

He said: ‘My grandmother explained things to me while I was there.

‘I can remember quite a lot, yes, well, particularly what I was dressed in and what the barber did to me before.’

Beaming as he is introduced to each of the women, including climate activist and author Yvonne Harris and former adoption worker Carol Bowyer Shipley, he jokes about the practicalities of wearing the crown.

In the 90-minute documentary, King Charles tells the women he could remember ‘quite a lot’ of his mother’s coronation, despite being just four years old at the time

In the summer of 1953, 50 young women from across Canada were sponsored by Canadian businessman and philanthropist Garfield Weston to travel to the UK

The group, who were around 17 years in age and in many cases had not even left their home home towns before, sailed across the Atlantic on the Empress of France to reach Liverpool, where they boarded a train down to London for the historic event

King Charles III is crowned with St Edward’s Crown byThe Archbishop of Canterbury, the Most Reverend Justin Welby on May 6 last year

The King admitted to the women that the crown is ‘very heavy’, revealing that it weighs five pounds

He said: ‘I remember it all so well then, because I remember my sister and I had bath time in the evening.

‘My mama used to come up at bath time wearing the crown to practice. You have to get used to how heavy it is. I’ve never forgotten, I can still remember it vividly.’

He added: ‘It is very important to wear it for a certain amount of time, because you get used to it then.

‘But the big one that you’re crowned with, the St Edward’s Crown, it weighs five pounds.

‘It is much heavier and taller, so there’s always that feeling of feeling slightly anxious, in case it wobbles.

‘You have to carry it, you have to look straight ahead.’

The king said he was ‘so glad to have had the chance to see you.’

‘I hadn’t realised you came over all those years ago,’ he said. ‘It’s a great joy to meet you all, after all these years. Take care, bless you.’

Told he must come back soon, the king laughed: ‘Yes, if I am still alive!’

It was, sources, have stressed, simply a joke by the King, not realising he would be diagnosed with cancer little more than a month later.

Ms Bowyer Shipley said of the meeting, which left some of them in tears: ‘It’s as surreal as being chosen in 1953. He really connected with us. There was humour and grace and we were chuckling a little a bit, as if he were a friend.’

The King and Queen have been sent the film to view. His Majesty had to cancel plans to visit Canada this year because of his cancer diagnosis but hopes to visit the country ‘before not too long’.

A royal aide said: ‘It is a really beautiful lyrical piece of film-making. It’s not a royal documentary but it is incredibly, profoundly moving and life-affirming and highlights both the enduring friendship between both the women and the Canada and UK, and how the Royal Family can cement those bonds,’ he said.

The documentary, by Canadian filmmaker Douglas Arrowsmith, will be aired on Boxing Day in Canada with an international release next year