The Crown star Josh O'Connor has described the culture secretary's calls to add a disclaimer to Netflix's much-talked about regal drama as "outrageous".
The streaming giant's lavishly produced series arrived last month and has been in the headlines since, attracting criticism for allegedly not doing enough to ensure viewers know it is a work of fiction.
Season four features Diana, Princess of Wales (Emma Corrin) and dramatises her relationship with the Prince of Wales (O'Connor).
Oliver Dowden, the Culture Secretary, had asked Netflix to add a disclaimer to episodes, a request the US company denied.
Now O'Connor has defended The Crown, accusing Mr Dowden of dealing a "low blow".
He told the LA Times' The Envelope podcast: "We were slightly let down by our culture secretary, whose job it is to encourage culture.
"In my opinion, it's pretty outrageous that he came out and said what he said. Particularly in this time when he knows that the arts are struggling and they're on their knees, I think it's a bit of a low blow."
O'Connor, who has earned critical acclaim for his portrayal of a young Charles, said viewers are aware The Crown is a work of fiction.
"My personal view is that audiences understand," he said. "You have to show them the respect and understand that they're intelligent enough to see it for what it is, which is pure fiction."
Earlier this week Netflix said it had "no plans – and sees no need" to add a disclaimer.
Helena Bonham Carter, who plays Princess Margaret in the third and fourth series, said the show has a "moral responsibility" to make it clear to viewers it is a drama and not historical fact.
In an interview recorded for The Crown's official podcast after filming on season four finished earlier this year, Bonham Carter discussed the differences between "our version" and the "real version".
Peter Morgan, who created The Crown, had previously appeared on the show's official podcast to defend his right to creative licence.
However Earl Spencer, Diana's brother, has indicated his support for a disclaimer being added.