Yet while Benson admits Kieslowski's thematic interests and visual style were an inspiration, he never set out to copy the structure of the trilogy. Instead, it was only after the Columbia University graduate sent his initial script to actress Jessica Chastain (who he'd befriended after meeting at the Malibu Film Festival) that the idea evolved.

"We just had this script and then we developed this character, and all of a sudden it became this two-movie project," he says. At the time, Chastain was working on Terrence Malick's , about to burst onto the Hollywood scene (she's since gained two Oscar nominations, for and ).

Benson asked Chastain to play Eleanor, in a script that was written from her husband Conor Ludlow's point of view. "I said, 'I would love to because I really believe in you, but I would like to also have the female perspective. I want to know why she disappears, where she goes, who's in her life…' And then he went and wrote . And it was really special," Chastain says.

With two scripts, one showing Conor's viewpoint and the other Eleanor's, the combined result is a film about how a couple deal with themselves and each other - in this case after the death of their infant son has torn them apart. "All of a sudden I had this film that was based on perspective. I had his side and her side, and we thought that was pretty interesting to at least try to film," says Benson, who until now had made only short films.
Casting James McAvoy as Conor, Isabelle Huppert (one of Chastain's idols) as Eleanor's red-wine-swilling mother and William Hurt as her father, and indeed make for an intriguing 190-minute viewing experience. Containing some overlapping scenes, "you can view them however you want to view them", says Benson. "They each contextualise the other. I don't think the order really matters. There was never really an intention of how exactly they should be watched, and I want the audience to watch it in whatever way they want to."

There's yet another twist in the tale. After the Weinstein Company bought the film at Toronto for international distribution, Benson went back to the cutting room to produce , a third version that splices footage from and . "There were a lot of other people who were asking me the question, 'Can these two films be one?'" the director says. Sitting with his editor in February, he produced a film about 70 minutes shorter in length than the combined running time for and .

Chastain compares the fact that there are now two versions, and , and also , with the concept behind Assayas' sublime terrorist thriller , which was originally made for French television but later reduced in length for cinemas. "I watched the five-hour version. I've seen it many times and I love it," she says. "Most people in the United States have seen the two-hour version, and it's very good, but I prefer the long version of any film."

With premiering this year at Cannes, now truly lives up to the hype as an "unprecedented cinematic experience". For starters, it offers a marketing challenge to distributors: do you screen and or do you release or perhaps all three? And if so, which way round do you feed them to the audiences?

Thus far, different territories are choosing different options. "I think Belgium is playing and and Spain is playing all three," Benson says. "I know the US will play all three. It's a conversation we're still having, but for me it's exciting to give audiences the choice, to see how they want to see it, and experience it how they want to experience it. I'm not going to tell any distributor how they should do their job."

The filmmaker is more reserved when it comes to whether there was pressure on him to cut the more distributor-friendly . It's an obvious question, however, given is now in the hands of Harvey Weinstein, the movie mogul notorious for recutting projects.

Whichever way the audience watches Benson's film(s), what's evident is a stirring portrait of grief - one that's so strong, McAvoy initially turned the project down because he'd just become a new father. While Conor tries to bury himself in his ailing restaurant business, Eleanor - named after the Beatles song - is traumatised by her loss. "Eleanor, when we meet her, has been denied being a mother," Chastain says.

"She's already suffered her great tragedy. And there's a sense she's [metaphorically] disappearing … She's trying to figure out, 'How do I survive? Is it possible to survive? I get tired of grieving. I don't know how to stop the grieving.' I read a lot about women who had lost children, and one recurring theme is trying to re-invent oneself and begin again as a new person."

Benson is now looking to begin again after such an epic film debut. Considering two options - an adaptation of a book he's been offered by the Weinstein Company and an original character piece set in the Los Angeles music industry that he's writing - the one thing he can't face is another movie about Eleanor or Conor.

"I'm done. I'm moving on. I've spent so much time with these people. I want to let go and find something completely different."

The Disappearance of Eleanor Rigby: Her The Disappearance of Eleanor Rigby: Him