NEW YORK, NY.- Barry Manilow is superstitious.

Such a statement may come as a surprise to anyone familiar with the 80-year-old pop legend’s career, with decades of hits, endless Las Vegas residencies and international fame as a still-smooth crooner who wrote the songs that made the whole world sing.

Yet, there is one thing Manilow has always pined for that now inspires some irrational fears: a Broadway show.

For nearly 30 years, that goal has proved tantalizingly out of reach despite a labor of love: “Harmony,” a musical he composed with his longtime collaborator Bruce Sussman, the lyricist who also wrote the show’s book.

“Harmony,” which follows the unlikely story of a sextet of 1930s singing and vaudevillian stars — the Comedian Harmonists, torn apart by the rise of Nazism and World War II — is now scheduled to open Monday at the Ethel Barrymore Theater. Barring, of course, some cosmic catastrophe that both Manilow and Sussman joke about.

Sort of.

“We keep thinking the theater is going to get hit by a tornado,” Manilow joked over lunch in midtown Manhattan in September after their first day of rehearsal.

Sussman, 74, laughed along: “It’s got to be something.”

Not to jinx the opening, both men offer a “kinahora” — a Yiddish locution meaning “no evil eye.” It’s a dash of dark humor that is not completely unfounded, considering the tortuous route that “Harmony” has taken from page to the Barrymore’s stage. Sussman first conceived of the show in the early 1990s after seeing Eberhard Fechner’s 1977 documentary about the Harmonists in New York.

“I came out of there and went to a phone booth on Lafayette Street, and I called him and I started babbling away,” Sussman recalled. “And he said, ‘I’m in.’”

Both men were immediately intrigued by the story of a popular singing group (they had played Carnegie Hall, for instance, in 1933) that was destroyed by — and lost to — history. Half of the group was of Jewish descent, and the Nazi takeover of Germany would eventually silence them.

But the urge to compose a musical was also deeply seated in Manilow, who says he was never interested in pop music as a child in Brooklyn, when he was already a precocious musician, playing accordion and piano.

“It wasn’t interesting enough for me,” Manilow recalled, of pop. “I didn’t know what was on the Top 40. I was into jazz and Gerry Mulligan and Chet Baker. I was into classical music. And I was into Broadway scores.”

He added: “And I memorized every note from every one of those albums. And that started it off.”

Manilow played piano in bars, worked in the CBS mailroom and wrote a raft of jingles, something he says that taught him to write a “catchy melody in 15 seconds.” (He and Sussman, both of whom are Jewish, met in New York in the early 1970s.)

Still, Manilow says that it was his sudden pop stardom — beginning with ballads like “Mandy” and continuing with later earworm hits like “Copacabana (at the Copa),” which Sussman helped write — that somewhat sidetracked his desire to write for the stage, though Manilow did do a series of Broadway concerts over the years.

“You can either write, ‘I love you’ or ‘I miss you,’” Manilow said of his masterful Top 40 songcraft. “You go any further than that, you’re writing a Broadway song.”

Despite his superstardom — and yes, probably because of it — “Harmony” did debut at La Jolla Playhouse in San Diego in 1997, but got mixed reviews and failed to transfer. Still, interest in the show continued to percolate, including in 2003, when an out-of-town tryout in Philadelphia — before a planned Broadway run — suddenly evaporated when financial backing disintegrated.

More iterations followed: In 2013 and 2014, the show had runs in Atlanta and Los Angeles, where the Los Angeles Drama Critics Circle recognized the two men for their score. Again, producers expressed interest in Broadway, but deals fell apart, something Sussman seems remarkably measured about.

“The gantlet that a new musical goes through, every step can be the end,” he said. “You do a reading, it’s over. You survive the reading, you do a workshop, it’s over. You survive the reading and you go to a regional and it’s over. And we all know shows that I’ve done that have died at one of those steps. We never did.”

Manilow was a little less sanguine about the process. “I put it in the drawer many times,” he recalled. “It was so heartbreaking every time it didn’t make it.”

During the coronavirus pandemic, however, Sussman and Manilow started to “kick the tires” on the show again with Warren Carlyle, the British director and choreographer who won a Tony Award in 2014 for his work on “After Midnight” and was nominated for Tonys for his work on the revivals of “Hello, Dolly!” (2017) and “The Music Man” (2022).

One possible turning point in the show’s luck, Carlyle said, was the addition of a narrator character — an older rabbi played by Chip Zien — who walks the audience through the various eras of the show.

“It was massive,” he said. “For me as director, it unlocks the whole show because previously it was kind of a six-headed dragon. You know there were these six guys: They all have wonderful stories. They all have rich lives. And I just didn’t know who to follow and I didn’t know how to focus the show.”

To solve the problem, Sussman suggested splitting the existing role of one of the Harmonists in two. In addition to his younger self, the show would also include his older self, a rabbi, serving as a narrator. “And suddenly for me, it was like, now the story has a point of view,” Carlyle said.

Following that work, the show was staged in 2022 at the Museum of Jewish Heritage — A Living Memorial to the Holocaust, where audiences — and critics — seemed to respond in ways that they hadn’t before. Writing in The New York Times, Elisabeth Vincentelli praised the songs “crafted in a defiantly classic mold,” which steer the show back to “solid emotional ground.”

She also noted the creative team’s ability in “balancing the shifting moods, which is no easy feat because they must shuffle broad humor and, well, Nazis.”

Zalmen Mlotek, the artistic director of the National Yiddish Theater Folksbiene, which presented “Harmony” at the museum, said he had heard about “Harmony” after a recommendation from developer Bruce Ratner, the chair of the museum.

“When I heard that Manilow and Sussman had written a piece about the Holocaust, I looked at it, the idea of the Comedians, this singing group, had had their careers destroyed, it was just very compelling to me,” he said.

Sussman and Manilow also said they were aware of a different relevance to their decades-old show when watching it last year at the museum, amid a rising number of antisemitic incidents in the country. That disturbing trend has only been amplified in recent weeks as war broke out in Israel and the Gaza Strip.

During the Folksbiene run, Sussman said, “I would sit in the back of the house and there’d be audible responses from the audience and certain lines, and I started getting nervous that people would think I was writing into the headlines. But some of those lines are 15, 20 years old.”

Most of the major cast members from the Folksbiene production have transferred to Broadway, though most are lesser-known performers, something that may make marketing the show difficult. And while Manilow knows he’s a draw — see all those years in Vegas — he’s also not performing, of course.

“I hope the show is strong enough to stand on its own,” he said.

Still rail thin and apparently indefatigable, he has been commuting from the West Coast, where he is still doing three shows a week at the Westgate Las Vegas Resort & Casino. (He just passed Elvis for the most shows ever at that resort.)

A onetime heavy smoker, Manilow is now a vaper, who — unlike his booming singing voice — is a quiet speaker. (Sussman still recalls seeing burn marks on Manilow’s piano keys where his Pall Malls would burn down as he composed.)

Sometimes standing to vape, he also conveys a nervous energy about watching a show from the audience for a change. “It’s a terrible, terrible thing: I see all the flaws and faults,” he said with a chuckle.

Still, he and Sussman said they hope to avoid any bad luck — theatrical, critical or otherwise — this time around.

“People say, you know, ‘Oh, you must be so excited?’” Manilow said. “I don’t know what I am, really. We’ve been just waiting for this moment for so many years.”

This article originally appeared in The New York Times.