Filming has begun on new film Spencer starring Kristen Stewart as Princess Diana - but is it a true story?

The British Royal Family’s history has been a popular topic for TV dramas and movies in recent years - from The Crown to The King’s Speech.

The latest director to reimagine the life of Princess Diana is Chilean born Pablo Larraín (No, Jackie), and he is confident his line-up of experienced actors will ensure a “stunning and beautiful” performance.

The movie’s producer, Steven Knight (Peaky Blinders) has confirmed that Spencer won’t be a rehash of previous biopics, since it’s not about Diana’s childhood or her tragic and untimely death.

A first look of the film showing Kristen Stewart in the leading role as Diana has just been released - but what is the film about and is it based on real events? This is what we know so far.

Who stars in the cast?

Twilight’s Kristen Stewart will play the lead role in the movie as Diana, in what she has described as an “intimidating as all hell” performance.

The full cast details of Spencer, including who will play Prince Charles and their two sons, Harry and William, has not yet been revealed.

However, Timothy Spall (Enchanted, The Last Samurai), Sally Hawkins (Paddington, Maudie), and Sean Harris (Mission: Impossible, Deliver Us from Evil) have all revealed they will feature in the film.

What is ‘Spencer’ about?

The movie is based around one weekend when Diana realised there was no possibility of salvaging her marriage with Prince Charles.

Stewart will play Diana at 29, as she reflects and reflects at a time when the ‘People’s Princess’ was reflecting on the anguish she was experiencing as her marriage collapsed, and the concerns she had for her two young sons.

Spencer - so-called because of Diana’s maiden name - is based around Christmas time at the Windsor Castle on the Royal’s Sandringham estate, the house where the British Royal family continues to celebrate festivities as a large extended group.

Stewart said the story was: “a dive inside an emotional imagining of who Diana was at a pivotal turning point in her life.

“It is a physical assertion of the sum of her parts, which starts with her given name; Spencer.

It is a harrowing effort for her to return to herself, as Diana strives to hold onto what the name Spencer means to her.”

Is it based on true events?

Though there is very little which can be verified, it is largely believed that in December 1990, Princess Diana realised her marriage was no longer salvageable.

She is thought to have reached this conclusion while on a Christmas break at Windsor Castle, with her two sons and Prince Charles.

Diana famously told BBC’s Panorama in 1995, the year before she and Charles divorced, that “there were three of us in this marriage, so it was a bit crowded,” referring to Charles’ relationship with Camilla while he was married to Diana.

Though this revelation came after the movie is set, Diana confronted Camilla about the affair at Camilla’ sister’s birthday party in 1989 - therefore she would have been aware of it at the time the movie is set.

Prince Charles revealed to Jonathon Dimbleby in 1994 that he had rekindled his relationship with Camilla Parker-Bowles in 1996, when his marriage to the late princess had already “irretrievably broken down”.

While no one will know for certain how Diana felt in these lonely days when she ultimately decided her decade of marriage was over, Lady Di did keep a remarkable journal of audio tapes, interviews and letters, which provide evidence of her concerns over both her and Charles’ extramarital affairs.

Diana once described how “[Charles] made me feel so inadequate in every possible way, that each time I came up for air he pushed me down again."

She was also heard on tapes in 1992, declaring she had been “deeply in love with someone” in the mid 1980s, who was not her husband and that she was “quite happy to give all this up [and] just to go off and live with him".

It is largely believed she was referring to her security guard, Royal Protection Officer Barry Mannakee, who was later removed from his role and transferred to the Diplomatic Protection Squad.