The regal drama has attracted criticism for its use of creative licence, particularly since the release of series four, which covers the early years of the relationship between Prince Charles and Princess Diana.
Oliver Dowden, the Culture Secretary, is expected to write to the US streaming giant this week, raising concerns that some younger viewers may mistake The Crown as a work of fact.
Helena, who plays Princess Margaret on the show, discussed the differences between “our version” and the “real version” in an interview for The Crown’s official podcast.
She said: “I do feel very strongly because I think we have a moral responsibility to say, ‘Hang on guys, this is not… it’s not drama doc, we’re making a drama’.
“So they are two different entities.”
Earl Spencer, the brother of Diana, Princess of Wales, has called for Netflix to add a disclaimer making it clear The Crown is a work of fiction.
Speaking to Alan Titchmarsh on Love Your Weekend, he said: “The worry for me is that people see a programme like that and they forget that it is fiction.
“They assume. Especially foreigners – I find Americans tell me they watch The Crown as if they’ve taken a history lesson. Well, they haven’t.”
He added: “It is very hard. There is a lot of conjecture and a lot of invention, isn’t there? You can hang it on fact but the bits in between are not fact.”
The Crown creator and writer Peter Morgan had previously appeared on the podcast to defend his right to creative licence.
Discussing much-criticised scenes in which features the late Lord Mountbatten sending Prince Charles a letter admonishing his pursuit of Camilla Parker Bowles, who at the time was married.
He said: “In my own head I thought that would have even greater impact on Charles if it were to come post-mortem, as it were. I think everything that’s in that letter that Mountbatten writes to Charles is what I really believe, based on everything I’ve read and people I’ve spoken to, that represents his view.
“We will never know if it was put into a letter, and we will never know if Charles got that letter before or after Mountbatten’s death, but in this particular drama, this is how I decided to deal with it.”
Meanwhile, former royal butler Paul Burrell said the new season is a “fair and accurate dramatisation” of the royal family’s treatment of Diana.
The Crown is available to stream on Netflix.