Susan Sarandon as Bette Davis, left, and Jessica Lange as Joan Crawford. (Kurt Iswarienko/FX)

“Feud: Bette and Joan” chronicles the cruel rivalry between two women during the making of 1962’s “What Ever Happened to Baby Jane?” — a horror film about a cruel rivalry between two women. You may be relieved to hear, then, that Susan Sarandon and Jessica Lange, who play Bette Davis and Joan Crawford, respectively, got along.

“Yes, we did,” Sarandon says with a laugh. “I said to Jess, at the closing of the whole thing, I said, ‘Thank God we got along,’ because [the project] was hard. It was really challenging.”

Series creator Ryan Murphy (“American Horror Story,” “American Crime Story”) echoes the sentiment. “We had a nervous first week, because we didn’t want to do impersonations. The first two days, I wanted to quit.”

“I was fighting against a female-impersonator version of [Davis], the cliche you see of her all the time,” Sarandon explains. “And she is over-the-top, so what do you do about that?”

Lange faced a different challenge. “I remember saying to Ryan, ‘I don’t know how to play this character. I don’t know who she is.’ ” Lange gained insight after researching Crawford’s childhood and, she says, “acknowledging the incredible artifice, the creation of Joan Crawford,” and then playing to what was “always just barely beneath the surface.”

Getting behind such facades is precisely what the series, which premieres March 5 on FX, endeavors to do. Fans and foes have long bathed in the gossip of Bette and Joan’s enmity: While filming a fight scene, Davis actually kicked Crawford in the head. Crawford wore weights during a scene when Davis carried her to exacerbate Davis’s back pain. Such details typically call to mind sound effects of screeching cats. “Feud” is different.

“Getting eight hours, you have a chance to delve into the complexity,” Sarandon says. “It was a bigger question than just their b----iness.” (Like much of Murphy’s work, “Feud” is an anthology. The second season is subtitled “Charles and Diana.”)

(Kurt Iswarienko/FX)

(Kurt Iswarienko/FX)

In the first episode, Olivia de Havilland (Catherine Zeta Jones) clarifies to an interviewer, “Feuds are never about hate. Feuds are about pain.” And these depictions of Davis and Crawford are heartbreaking. We meet them in their 50s as alcoholics whose careers have dried up because, as Jack Warner (Stanley Tucci) rhetorically asks, “Would you give either of these broads a toss in the hay?”

The notoriously shrewd Warner Bros. boss encourages “Baby Jane” director Robert Aldrich (Alfred Molina) to manipulate Davis and Crawford, keeping them at each other’s throats because rumors of the on-set antics would sell more tickets later.

“Feud” also asserts that Warner and his ilk are the reason Bette and Joan battled to begin with. “They were fighting a culture that has ‘It Girls’ that says there is only one girl at a time,” Murphy opines. “It creates a competitive culture, and men use that to their advantage by pitting women against each other.”

“It minimizes the power they have collectively,” Sarandon adds. “And that still is going on. Every ‘Real Housewives’ of wherever — the least imaginative story line is always the women pitted against each other.”

Catherine Zeta-Jones as Olivia de Havilland. (Kurt Iswarienko/FX)

The surprise success of “Baby Jane” launched an entire genre of horror, unflatteringly labeled Psycho-Biddy. These films typically feature an older, crazy, murderous and — most damningly — jealous woman. Davis and Crawford would go on to star in several. “It’s like Joan says [in the first episode],” Lange recalls, “there are three roles for women in Hollywood: the ingénue, the mother or the Gorgon. They had gotten to the last period.”

“Baby Jane” is pure camp. And Murphy does layer in echoes of the film — for example, when Crawford spies a larger number on Davis’s contract, a sting of horror music plays. But these moments are more than just homage. “Treating inequality and sexism as a horror movie — that’s what I tried to do,” Murphy says. (The idea calls to mind what Jordan Peele’s film “Get Out” does, more overtly, with the topic of racism.)

Not that “Feud” doesn’t have a light touch. It brims with juicy details (Crawford washed her face with witch hazel and ice cubes every morning) and historical figures (gossip columnist Hedda Hopper, played by Judy Davis, and her many fabulous hats). Murphy says, with endearment, “Some of the stuff these women did was bats--- crazy and hilarious.”

Several factoids, such as the tidbit that Davis’s wig in “Baby Jane” had been worn by Crawford in a previous picture, came to Murphy directly from Davis’s mouth. He wrote to her as a child, and she wrote back. They kept up a pen-pal relationship, and when he became a journalist, more than a decade later, she granted him an interview. “I had never been to L.A. before,” he says, recalling his arrival at Davis’s door, with flowers, a couple of months before her death. “She dressed up for me. She was wearing a Patrick Kelly suit and a wig.”

The 20-minute interview turned into four hours. “We just chain-smoked in her living room,” he says. “I ran out of questions and started asking her very personal things.”

Sarandon, left, with Lange in “Feud.” “Television has stepped into the void that movies left for actresses,” Lange says. (Suzanne Tenner/FX)

Murphy asserts that he made the project from “a real place of love and respect. Both women were misunderstood and were victims of their time. They died alone, underappreciated and unhappy.” Have times changed?

“Ageism is huge in our culture, the idea that beauty is equated with youth,” Lange says. “I am not in a romantic film with a man who is 20 years younger. But no one would think twice about casting a man in his 60s with a leading lady in her 30s. That has a lot to do with the fact that men are at the helm — and maybe they have some kind of inflated idea about themselves.”

But both actors cited a strong sense of camaraderie among women in the business today. Sarandon is hopeful about the rash of female comedians who’ve had success “making great films that star a bunch of women — Amy Poehler, Amy Schumer, Melissa McCarthy, Tina Fey.”

And Lange argues “that television has stepped into the void that movies left for actresses. Some of the best work by women, in the last 5 or 6 years, has been on television.” (Lange has won two Emmy awards working with Murphy in “American Horror Story.”)

“That is a modern idea — that women are better and stronger together, unified as a force,” Murphy says. “It was a tragedy that [Davis and Crawford] could have been allies and friends. They had more in common than anyone at the time. They were both married four times, Academy Award winners, single mothers. I wish they had unified. I think that they would have been happier.”

Sarandon, left, Ryan Murphy and Lange at a "Feud" event in New York on Feb. 13. (Rabbani And Solimene Photography/Getty Images)

Sarandon and Lange have much in common with Davis and Crawford as well, as Academy Award-winning actors in the third act of their careers. In fact, they are each more than a decade older than their on-screen counterparts were in 1962. “It shows how far we’ve come in terms of taking care of yourself and living healthier,” Murphy says.

Further, Sarandon and Lange, as producers on “Feud,” have a financial stake in the property, as Davis and Crawford did in “Baby Jane.”

“Susan and Jessica gave Bette and Joan the happy ending that they should have had,” Murphy says. “They realized that the way to win was to win together.”