Actress Gillian Anderson, who stars as Raynor Winn, said the allegations that the memoir behind "The Salt Path" was fabricated felt like a betrayal, just as the film's US and Canadian release dates were pushed back.
Anderson revealed she felt "betrayed" by allegations that The Salt Path memoir was fabricated after spending time with its authors.
The adaptation of Winn's 2018 memoir was released in the UK last year and tells how the couple, Raynor and her husband Moth, walked the South West Coast Path after losing their home.
The memoir also recounted how Moth was diagnosed with a neurological condition, however The Observer reported last year that Winn may have misrepresented the events that led to the couple losing their home and that experts doubted Moth having corticobasal degeneration.
It was also revealed that the couple's legal names were Sally and Timothy Walker.
Winn previously described the Observer's article as "highly misleading" and said the couple had been taking legal advice.
Anderson, who plays Winn in the film, said the reports indicating claims were fabricated was "really disappointing".
"We had been so surprised by its success: 'What, really, this film about two old people going on a walk?'" the Sex Education star, 58, told The Times.
"It felt like such a betrayal because we'd spent time with [the Winns]."
She has not heard from the couple since the allegations broke, the outlet reported.
Anderson also spoke about the controversy with The Radio Times last week, saying: "It's very unfortunate. The film was doing really well in the UK, beyond my expectations. I think we were about to sign with Sony Classics for the United States the week when the article came out, so it sucked, and continues to suck."
"A lot of people were enjoying it, regardless, and it is special in its own right. I hope people are able to experience it as its own entity, separate from what may or may not be true or whatever controversy there is."
Impact on North American release
The Salt Path was originally set to be released in the US and Canada on May 22 but has been pushed back to September 4. The postponement means Canadian theatres will see the film several months later than originally planned, and the delay could affect the film's momentum in the United States where Sony Classics had been preparing a launch.