Princess Margaret's former lady-in-waiting confronted Helena Bonham Carter about her "awful" performance in 'The Crown'.
Lady Anne Glenconner - who served the princess from 1971 until her death in 2002 - admitted she was "mad with fury" when she watched the Netflix regal drama, having invited the 56-year-old actress to tea to discuss her friend's mannerisms.
But she claimed Helena insisted she had "no choice" in how she appeared on screen.
Anne - who was played in season three of the show by Nancy Carroll - told Oldie magazine: "I saw Helena Bonham Carter - she came to tea - about acting Princess Margaret: how she spoke and walked. I said I never saw her run.
"After seeing Helena in 'The Crown', I was very disappointed with the portrayal and told her, 'It was rather awful, wasn’t it?'
"She said she had no choice other than to do what she was told."
The 90-year-old former royal companion claimed the production "couldn't afford to film" at her ancestral home and hit out at the "cheap" scenes of her and Margaret together.
She said: "When they filmed Princess Margaret first meeting Roddy Llewellyn, we were sitting by a pool at what looked like a ghastly country club, they had me pimping for her, with us both in bikinis — Princess Margaret never wore a bikini. So cheap.
"They really should put a disclaimer at the beginning of 'The Crown', saying it isn't true."
Helena - who played Margaret in the third and fourth seasons of the show - recently admitted she thought the programme should end because it has almost caught up to the present day.
She said: "I should be careful here, but I don't think it should carry on, actually.
"I'm in it and I loved my episodes, but it's very different now. When 'The Crown' started it was a historic drama, and now it's crashed into the present. But that's up to them."
The 'Harry Potter' actress previously suggested that Peter Morgan's drama had a "moral responsibility" to remind viewers that they are not watching a documentary.
Helena said in 2020: "I do feel very strongly because I think we have a moral responsibility to say hang on guys, it's not a drama doc, we're making a drama. They are different entities."
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