Prince delivers ... what?

Following a preview of “LoveMusik,” Joel Grey approached the legendary director Harold Prince, who staged the new Broadway musical. “Hal, I love this show,” said the actor who starred in Prince’s original Broadway production of “Cabaret.” “But what exactly is it?”

Grey is not alone in puzzling over the intimate musical, which opens Thursday. Preview audiences have not quite known what to make of the show, which circumambulates through the bohemian marriage of Kurt Weill, the German-born composer best known for “The Threepenny Opera,” and his muse, Lotte Lenya, who starred in that classic. The style of “LoveMusik,” dotted with numbers from Weill’s eclectic songbook, incorporates elements of German expressionism, vaudeville, ‘40s musicals and torch-song cabaret. The shifting tone reflects the permutations of a couple who loved as large as they lived, reinventing themselves during the turbulent ‘30s and ‘40s as they moved from Europe to America.

Prince professes to be delighted with Grey’s response. “There’s a moment I love a lot, common to a bunch of shows that I’ve done, where I say, ‘I’m flying a little blind here,’ ” says the director, sitting in his book-lined office at Rockefeller Center, surrounded by mementos of a nearly six-decade theatrical career that has brought him a record 21 Tony Awards. “Don’t ask me to describe why this is shaped that way or how that got shaped that way. I can’t explain it. But I do know that it’s unsettling in the best possible way.”

Emotional center

At 79 and rich as Croesus thanks to his phenomenal “Phantom of the Opera,” Prince is still boyishly enthusiastic about advancing the musical form -- the prevailing ambition of his life and career since his breakthrough as a director in 1966’s “Cabaret.” That followed his early start as a producing wunderkind behind such hits as “Damn Yankees!” and “West Side Story.” His experimental daring culminated with a string of landmark musicals in the ‘70s with Stephen Sondheim that included “Company,” “Follies,” “A Little Night Music,” “Sweeney Todd” and “Pacific Overtures.”

Prince’s profile has dimmed of late, however, following the failure of his 2003 reunion with Sondheim on the musical “Bounce,” which had generated high expectations because of its pedigree. Heightened curiosity swirls around “LoveMusik,” as well, with its book by Alfred Uhry (“Driving Miss Daisy”) and cast led by Michael Cerveris and Donna Murphy.

Experience has taught the director to ignore buzz in favor of getting to the emotional core of the show. “There are some shows where you strain to get there, but this time I was born there,” he says, noting that from the moment he read the book “Speak Low (When You Speak Love): The Letters of Kurt Weill and Lotte Lenya,” he was confident it could translate into a musical.

His affinity for the material is apparent: “the divine decadence” of the Weimar Republic; the bedeviling institution of marriage; and the tension between art and commerce, personified in the querulous Bertolt Brecht (David Pittu), who constantly needles his early collaborator Weill for selling out to Broadway and Hollywood. But “LoveMusik” cuts closer to the bone for Prince than many of his other shows. Despite his skepticism of atavism, the director says his German-Jewish roots explain, at least in part, his affection for German artists, like Emil Nolde, and filmmakers like Friedrich Murnau, which is reflected in the look of the show. And though he never met Weill, who died in 1950 at 50, he knew and loved Lenya, who starred in “Cabaret” and remained a lifelong friend of Prince and his wife, Judy.

“She was a flirt, smart, funny in a smart-ass way, and a total delight to be with,” says Prince, pointing out a picture of himself with Lenya, Jack Gilford, Jill Haworth and Bert Convy on the first day of rehearsals for “Cabaret.” As Weill’s widow and keeper of the flame, Lenya was a lodestar for that production, singing songs by John Kander and Fred Ebb that were a homage to the Weimar-era classics she introduced, including “Mack the Knife,” which is featured in “LoveMusik.”

That Weill and Lenya got together in the first place was something of a miracle. He was the son of a Jewish cantor, she the Catholic daughter of an alcoholic lowlife who pimped her on the streets when she was 13. They married in Berlin in 1926, divorced in 1933 after Weill left for Paris and she moved in with a con man. They remarried in 1937 when they reunited in New York. Lenya’s early emotional scars might well explain her infidelities -- which Weill encouraged for his own erotic reasons (he had mistresses on the side). But the real “other woman” for the workaholic Weill was music.

As he did in “Follies,” Prince contrasts the gritty reality of the relationship with the romantic artifice apparent in some of Weill’s Broadway musicals.

“This is a musical in which you just keep peeling away the layers,” says Prince. “You see more and more of Weill and Lenya -- the good, the bad, the romantic and the impatient. And what you end up with is that life is not this big happy journey for anybody. And yet, we’re all here, still journeying, and [as a marriage] it worked. It worked because they really did love each other and because they were irreplaceable in each other’s lives.”

Uhry says he wondered at first if he could do justice to such an emotionally complicated relationship, but that Prince provided a “safe” environment in which to experiment. “We were certainly not thinking of breaking convention,” he says. “Hal said, ‘Just tell the story in the best way you know how.’ ”

Straight to Broadway

Instead of taking the usual route of workshops and regional tryouts, “LoveMusik” is opening cold on Broadway. “That’s really scary,” Uhry says. “But both Hal and I were fairly secure in the material. It’s a sophisticated play for New York audiences so I guess we have to be a little crazy to jump in the water like this.”

As someone who won his first Tony Award at the age 24 for producing “The Pajama Game,” Prince is sympathetic to today’s pressure to “get successful quick” and the compromises that come with spiraling budgets. “I got successful awfully quick and I wanted it.... But I do think there is responsibility to move the musical theater form forward,” he says, praising Weill as a progenitor of the “concept” musical in which an overriding idea takes primacy over basic narrative, as in Weill’s “Love Life” and “Lady in the Dark.” “I think you always have to be aware of the work that came before and build on that.”

Win, lose or draw, Prince seems remarkably confident that he and Uhry have come up with the show they wanted to create. It will be up to audiences, he says, to decide how groundbreaking it may be. Or what “LoveMusik” is about for that matter. In other words, he’s hard-pressed to answer Joel Grey’s question at the preview: What exactly is it? “I haven’t a clue,” he says. “For me, it has always been a case of just getting the show on.”