'All of Us Strangers' director Andrew Haigh knew he had to make the film after being moved by the themes of grief and loss in the original book.

The upcoming fantasy film is based on the 1987 novel 'Strangers' by Taichi Yamada. The story follows screenwriter Adam (Andrew Scott) who meets the enigmatic Harry (Paul Mescal). As their relationship grows, Adam is pulled back to his childhood home, where it appears his parents are living there, just as they were on the day they died 30 years ago.

Before he signed up for the project, filmmaker Haigh, 50, read Yamada's tome and the premise instantly appealed to him.

Speaking to BANGPremier.com at the BFI London Film Festival, Andrew said: "I was sent the book by the producers and I loved the central idea of the novel, which is someone who lost his parents meeting them again, and having a relationship with his parents once again, and how that opens up a lot of things he had been storing inside.

"A lot of pain, a lot of trauma, and how he kind of comes to terms with that."

Producers Sarah Harvey and Graham Broadbent agreed with the filmmaker, and the former admitting the book's story had stayed with her for 20 years.

She said: "Well, I read the book 20 years ago and it really stayed with me till we finally managed to get the option for the book five years ago. I think it had a really universal concept.

"At it's heart is love and loss and, I think, as a producer, all you have got is your instincts. If something has stayed with you for 15 years, it means you probably need to explore it and try and make it as a movie."

Graham added: "It's a very relatable concept. What if you could go back in time and talk to your parents from years gone by? To right the wrongs, to have the conversations you might have had then.

"And I think the smart thing that we did was get Andrew Haigh on, and he's a brilliant writer and director. Andrew owned the story and took it to a place that was entirely his own."