NEW YORK — Barry Manilow is going back to his first love — not Mandy, but musical theater. 

Almost 50 years after he was nominated for his first Grammy, producing Bette Midler’s “The Divine Miss M,” Manilow and longtime collaborator Bruce Sussman are finally bringing their original musical “Harmony” to the stage.

“I never really thought about becoming a singer or an entertainer or a performer. It never dawned on me,” the 78-year-old Brooklyn native said.

“I was going to be an arranger like Nelson Riddle or a Broadway songwriter. That was where I was heading until … that stupid ‘Mandy’ got in the way,” he said of his 1974 pop hit.

“Harmony,” which will have a a seven-week run beginning April 14 at the National Yiddish Theatre Folksbiene, tells the true story of the Comedian Harmonists, a group of six German men, several of them Jewish, who made up one of the most successful musical groups in Europe in the 1920s and ‘30s until the Nazis shut them down.

“The show is about the quest for harmony, in the broadest sense of the word,” Sussman said.

“Not only did the Comedian Harmonists find musical harmony; they found harmony in their lives. Some of them were Jews, some of them were gentiles, one of the Jewish members married a gentile woman, one of the gentile members married a Jewish woman. That was their quest for harmony, but unfortunately it was a quest for harmony in what turned out to be the most discordant chapter in human history.”

Sussman came up with the idea decades ago after sitting through a four-hour German-language documentary at the Public Theater in the East Village. But life, and Manilow’s own success, put their Broadway dreams on hold.

“Harmony” finally debuted in 1997 at the La Jolla Playhouse outside San Diego, then moved to Philadelphia in 2003, led by Brian d’Arcy James, but the money ran out. It took the stage in Atlanta 10 years later, but still never made it to New York.

Finally, it landed at the Folksbiene, where it was set to open for previews in February 2020. Then COVID hit.

Sussman used the two years off to do a massive rewrite. The show, starring Chip Zien and Sierra Boggess and directed by Tony Award winner Warren Carlyle, is finally ready for Manhattan.

“After all these years, to present it to this New York audience is what we’ve always wanted for ‘Harmony,’” Manilow said.

The Comedian Harmonists’ music was declared degenerate by the Nazis because it was Jewish, and they were ordered to stop playing music written by Jews, then banned from performing entirely. Their records were burned and they were wiped from memory, other than a few albums hidden under mattresses that kept their legacy alive.

“All I know is that these six extraordinary human beings should be remembered, and Barry and I are committed to doing whatever we can to make that happen,” Sussman said.

Putting on “Harmony” at the Folksbiene makes sense, the co-creators said. The century-old theater, which won a Drama Desk Award for its Yiddish-language “Fiddler on the Roof” in 2019, is meant to make people remember.

The timing of their show, amid Russia’s invasion of Ukraine, is not lost on them.

“There’s a line in the play where someone says ‘It’s the same old hate, just different costumes,’ and it certainly applies now,” Sussman told The News.

“The history we ignore is the history we are condemned to relive.”