When he set out to make his third film, “Bunker,” about a slow-burning conflict between two married people who have grown apart, Oscar-winning French director Florian Zeller had Stanley Kubrick’s “Eyes Wide Shut” in mind.

Like Kubrick, who cast then-married Tom Cruise and Nicole Kidman as a couple whose relationship is unraveling, Zeller wanted to exploit the permeability between fiction and reality by putting Penélope Cruz and Javier Bardem — partners for nearly two decades — on-screen as husband and wife.

“I loved ‘Eyes Wide Shut,’ this ambivalent proposition presented to the audience where you’re not quite sure what you’re being invited to watch,” Zeller says. With Cruz and Bardem, he says, he wanted to use “what they are to touch on something more authentic and more unsettling for the audience.”

“Is it fiction? Is it another version of fiction? Where is the line between reality and fiction?” With Cruz and Bardem, he says, he wanted to use “what they are, in the noblest sense of the term, to touch on something more authentic and more unsettling for the audience.”In fact, the prospect of bringing Cruz and Bardem together on screen came before the story. Zeller says he began “daydreaming about the idea of seeing them together on screen,” rather than writing two characters and then wondering who might play them. Although the actors had appeared together before, Zeller was intrigued that they had never played a married couple. “That permeability between reality and fiction seemed to me a truly fascinating project,” he says.