A BBC film is to feature exclusive footage of the King and Queen in the first year of King Charles's reign.

Camera crews were given access to King Charles III and Queen Camilla after the death of the Queen, leading up to the coronation and the months following.

The 90-minute documentary is narrated by actress Helena Bonham Carter, who played the late Queen's sister Princess Margaret in The Crown.

It is due to air in December, as part of the BBC's Christmas programming.

Charles III: The Coronation Year follows the King and Queen as they took on their new roles as sovereign and consort, and as Buckingham Palace planned the first coronation in 70 years.

A previously unseen image released from the documentary shows the King in a suit and tie, sitting in the Coronation Chair during one of the dress rehearsals in Westminster Abbey ahead of his crowning.

The BBC said the programme features "moments of great poignancy and humour" and offers a "unique perspective on the inner workings behind a defining moment which marks a new era in the history of the monarchy."

Simon Young, the BBC's head of history, factual commissioning, said: "At the heart of this story is a man who is taking on the job that has always awaited him. Everyone wants to know how he takes on that challenge."

The King's first 12 months as monarch were filled with events including Remembrance Sunday at the Cenotaph, a state visit by the South African president, his first Christmas broadcast, Royal Ascot, Trooping the Colour and an overseas visit to Germany.

The King and Queen were crowned in May in a deeply religious ceremony, followed by a week of celebrations.

It is not known if there is any mention in the film of the more personal aspects of the King's life, such as his relationship with the Duke of Sussex whose memoir Spare and Netflix documentary were also released during his first year of reign.

Kate Phillips, who is responsible for the commissioning of unscripted content at the BBC, described the access given to the documentary crew as "extraordinary".

"It's a real privilege to be given such extraordinary behind-the-scenes access to the first year of King Charles's reign," she said.

"It is a remarkable time in history and this documentary will offer a unique insight into King Charles and Queen Camilla, and the preparation and planning leading to their coronation, a momentous ceremony watched by millions around the world."

It is not the first time the Royal Family has given TV cameras close access to their day to day lives - Queen Elizabeth and Prince Philip allowed the BBC and ITV to film behind the scenes for a documentary in 1969.