New York — A thorny, decade-spanning romance about infatuation undone by alcoholism, the “Days of Wine and Roses” musical began as a seed of an idea that took 21 years to bloom.

As star Kelli O’Hara recounts it, she had recently wrapped the brief Broadway run of “Sweet Smell of Success,” another musical adaptation of a mid-century cinematic classic, when she traveled to Utah for a Sundance Institute workshop in the summer of 2002. Assigned to work on Craig Lucas and Adam Guettel’s “The Light in the Piazza,” O’Hara quickly was smitten by Guettel’s sumptuous score. Interested in revisiting 1950s America with Brian d’Arcy James, her “Sweet Smell” co-star, she discussed with Guettel the idea of adapting “Days of Wine and Roses” — Blake Edwards’s 1962 film starring Lee Remick and Jack Lemmon — for the Broadway stage.

“I was in a place where I wanted to really dig my teeth into something rich and deep — not just your normal ingenue,” O’Hara says. “I just said to Adam, ‘You should write a really dark, operatic musical version of “Days of Wine and Roses” for Brian and me.’”

Guettel embraced the idea. “I remember saying she looks like Lee Remick or better,” he recalls, “and sounds like Teresa Stratas or better.” When James caught wind of the concept, he didn’t need any convincing. “The combination of Adam Guettel and Kelli O’Hara? You’d be a fool not to say, Sign me up’ — in any way,” James says. “I’ll get them coffee if that’s all that needs to be done.”

Three years later, the Broadway production of “Piazza” earned Guettel two Tonys, for original score and orchestrations, and O’Hara the first of her seven career nominations. Around 2011, Guettel secured the rights to adapt “Days of Wines and Roses” and began composing the music and lyrics for a stage show. In 2015, Lucas reunited with Guettel to write the musical’s book. Over the past five years, Michael Greif (“Rent,” “Dear Evan Hansen”) came onboard to direct, and O’Hara and James headlined a slew of readings and workshops.

This past spring, the duo starred in the acclaimed off-Broadway premiere of “Days of Wine and Roses” at the Atlantic Theater Company. Coasting off that momentum, the production transferred to Broadway for a limited engagement that officially opens Sunday and runs through April 28 at Studio 54 — bringing to fruition the vision O’Hara, James and Guettel shared back in 2002.

“The piece is really built on that kind of loyalty,” Guettel says. “I think everyone cares about the project a lot.”

James portrays Joe Clay, the hard-drinking New York public relations executive who woos O’Hara’s Kirsten Arnesen, a sweet-natured secretary who avoids alcohol until he introduces her to the chocolaty indulgence of a brandy Alexander. Over the course of a roller-coaster relationship, in which booze alternately ignites and smothers their romantic flame, the couple get married, raise a daughter, drift apart, collide again and take stutter steps toward recovery.

Although Guettel’s jazzy score is something of a throwback, with its lush melodies, whimsical woodwinds and opera-adjacent vocals, the show’s small cast and tough subject matter make it a far cry from Golden Age song-and-dance extravaganzas.

“It’s demanding of an audience in a very, very contemporary way,” Greif says. “So even if it’s a period piece, and even if the music in some ways hearkens a traditional musical theater language, there’s something that’s so modern and challenging about it.”

Lucas says that difficulty informed the decision to stage the production over 105 minutes with no intermission — forcing a heavy show to stay light on its feet. Greif’s staging adds visual flair, framing the stars in stylish silhouettes and using a pool of water downstage to shower them in shimmering reflections. While the musical largely follows the same beats as the movie (and the 1958 teleplay it was based on), Lucas challenged himself to prune the plot to its bare essentials and craft a show so propulsive that the audience can’t dwell on its despondence.

“I knew we were going to have to find a form for it that did not allow the audience the luxury of disengaging,” Lucas says. “So we didn’t want to have an intermission. That was going to be just enough permission for the people who were squeamish or made uncomfortable to disengage.”

Lucas and Guettel, both of whom have overcome their own struggles with alcoholism, took care to approach the subject with the right balance of modern nuance and period-appropriate authenticity. Take the depiction of Alcoholics Anonymous: While the film leaned into the novelty of the support group, which had been founded 27 years earlier and was still establishing itself in the mainstream, Guettel notes that the stage show avoids the kind of “preachy AA meetings” that have since been portrayed to exhaustion in various media. But that doesn’t mean the production imbues its characters with an anachronistic understanding of the disease.

“We tried very hard not to go into that sort of ‘been there, done that’ place, because of our modern audience,” Guettel says. “However, I believe firmly that we have to stay in that period, that we shouldn’t be indulging in what I would call presentism, and to ascribe our current feelings in society about all kinds of stuff and inject that into our show.”

The stage version also eschews the movie’s famously bleak ending, instead concluding on a note of bittersweet hope. And the show cuts several sequences from the film, including a sensationalist scene in which Joe, at rock bottom, is committed to a sanitarium, wrapped in a straitjacket and pinned down as orderlies sedate him.

“I’m a child of two alcoholics, and I am also an alcoholic and fortunately decades into recovery, but it’s a lived experience,” Lucas says. “I know a lot of people who have nearly died from alcohol poisoning, and I know people who have died from it. I’ve never known a single instance of a person being put in a straitjacket. So it feels hokey, as if it was created to shock the audience of 1962 into understanding the severity of the disease and its consequences.”

Although Henry Mancini and Johnny Mercer won an Oscar for the film’s title song, Guettel never considered using that tune as part of his score. “I adore that song — it’s really gorgeous — but that wasn’t going to be informing the stage musical,” he says. “Definitely not.”

Instead, Guettel focused on channeling the “flowing, rambunctious, improvisatory feeling” that pervaded jazz of the era. With O’Hara and James long attached, he also had the luxury of tailoring the score to their vocals. After the show’s creators toyed with the idea of spreading solos around the cast, the carefully crafted songs are ultimately performed by just three characters: Kirsten, Joe and their daughter, Lila (played by Tabitha Lawing).

“Adam Guettel does not make any random choice in terms of how a character expresses themselves and how the music is being delivered,” says James, a four-time Tony nominee. “It’s always informed by and defined by what the character wants or needs.”

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“Days of Wine and Roses,” through April 28 at Studio 54, 254 W. 54th St., New York; daysofwineandrosesbroadway.com.