Helena Bonham Carter believes hit Netflix series The Crown could be better called The Conjecture.

The star, who plays the colourful late Princess Margaret, thinks the show serves up speculation on mysterious royals.

Bonham Carter said she believes the royals have a good sense of humour and Margaret herself would be “amused” by her on-screen portrayal.

The actress hopes this portrayal will add more dimensions to the royals’ past characterisation by the press.

Bonham-Carter spoke on the red carpet of The Crown’s series three premiere in Mayfair, London, a short walk from Buckingham Palace.

She said of truly knowing the inner workings of Britain’s first family: “This is all projection. It’s very difficult.

“The whole point about The Crown is a lot of famous people we know nothing about.

The Crown Season Three Premiere – London
Tobias Menzies, Olivia Colman and Helena Bonham Carter arriving for The Crown season three premiere held at the Curzon Mayfair (Ian West/PA)

“It’s about the royal family and we ultimately know very little about them. It’s not The Crown, I call it The Conjecture. It’s a massive conjecture.”

Margaret was known for her romances and a lifestyle seemingly opposed to the regal reserve of her sister Queen Elizabeth, portrayed in the Netflix series by Oscar-winner Olivia Colman.

Tobias Menzies, who inhabits the role of the Duke Of Edinburgh, and the on-screen Prince of Wales Josh O’Connor also attended the premiere in London.

Bonham-Carter believes all the royals have a good sense of humour and Margaret, who died in 2002, would find The Crown particularly funny.

She said: “I hope, I think, she’d be amused. I think she would have been really amused by it. I think they all have a good sense of humour.

“Definitely Margaret, Princess Margaret has a great a sense of humour and a great sense of fun.”

On her own performance, she added: “I hope that she’d appreciate that I tried.

“I think she felt quite misrepresented in the press. I hope I made her multi-dimensional. A bit more full of colour.”

The Crown, created by Peter Morgan, is available on Netflix.