NEW YORK, NY.- For a moment, I had no idea what I was listening to. It was the last of day of September, and I was attending a rehearsal of “The Look of Love,” Mark Morris’ new evening-length dance set to songs by Burt Bacharach. But the vocals that the dancers were moving to in precise patterns sounded like modernist opera, not the meticulous 1960s pop that Bacharach is mainly known for. Then I caught a lyric: “Be careful of the blob.”

It was Bacharach, after all: the theme song he wrote for the 1958 sci-fi horror movie “The Blob.” And the next songs were immediately recognizable: “(There’s) Always Something There to Remind Me,” “I Say a Little Prayer” and, of course, “The Look of Love.” These are the hits, and there are more of them in Morris’ dance, which his company debuts Thursday at the BroadStage in Santa Monica, California, before taking it to the Kennedy Center in Washington.

Still, the weird version of “The Blob” was there to remind me that Morris’ take on Bacharach wouldn’t exactly be like the old records. The music is performed live, sung mostly by Broadway veteran Marcy Harriell, and the arrangements, by jazz pianist Ethan Iverson, take some liberties.

In that sense, the show resembles Morris’ last evening-length dance, “Pepperland,” a riff on the Beatles’ “Sgt. Pepper’s Lonely Hearts Club Band” that Morris created for a “Sgt. Pepper” festival in Liverpool in 2017. The music for that production was also played live, in arrangements by Iverson that occasionally make the familiar songs unrecognizable.

You might assume, then, that “The Look of Love” is a kind of sequel to “Pepperland” — similar time period, similar approach. But in an interview after the rehearsal, Morris said the idea for a Bacharach show came first, many years ago, when Iverson was serving as musical director for Morris’ company and the two men discovered a shared love for Bacharach’s music.

“This is great American music that people are either too familiar with or they’ve never heard it or they’ve never identified who wrote it,” Morris said. “People are always saying, ‘Oh my God, he wrote that?’ That’s why I’m doing it.”

Speaking over the phone while on tour in Germany, Iverson agreed. “I would put Bacharach up there with Gershwin, Cole Porter and Irving Berlin as part of the American Songbook,” he said. “These are songs you hear once and never forget.”

“But Bacharach is underrated, in terms of his sophistication,” Iverson continued. “Some people think it’s easy listening, but the details are subtle and very nerdy.” For example: the first measure of “Anyone Who Had a Heart,” Bacharach’s first hit with lyricist Hal David, is in the unusual meter of 5/4. That song is in “The Look of Love,” too.

Iverson said that, compared with his work on “Pepperland,” his approach to Bacharach’s music was “more reverent.” Inspired by Nelson Riddle’s arrangements for Frank Sinatra, he has composed some preludes and interludes that are more minimalist or out there, “because Mark needs those.” But mostly, “I really want to honor Bacharach as a composer,” he said. (“The Blob” is an exception: “I really put a hurting on that one,” Iverson said.)

Bacharach, 94, has had minimal input. Morris recounted a few Zoom sessions with the composer — “he was great and funny, and we basically saw the top of his head the whole time” — during which they discussed song choices and instrumentation. Bacharach wanted the band to include a trumpet player, a crucial part of the Bacharach sound, and it does. For Morris, the most important part of the exchange came when Bacharach said, “You don’t want it to be boring.”

“I was like, Thank Goddess!” Morris said. “We were scared to ask about changing things. He gave us carte blanche.” In an email message, Bacharach said that what he had seen of Morris’ work online made him excited for the show and that he felt his music was “in good hands.”

In many ways, “The Look of Love” resembles not just “Pepperland” but most of Morris’ work to vocal music, whether Bob Wills and the Texas Playboys or Baroque opera. As Iverson put it, “Mark is very good with songs that tell a story.”

At the start of “Say a Little Prayer,” when the lyrics are about waking up, combing hair and running for the bus, the dancers do those actions. On the word “heartbreak,” their fists tug their shirts at heart level. That kind of miming is a classic Morris device, which some viewers disparage and others love. So is the way that, by the time the instrumental break comes, those gestures have become choreographic motifs, deftly arranged to make musical sense.

The production, with costumes by Isaac Mizrahi, is simple in design. For props, there are pillows and folding chairs — an allusion, perhaps, to the chair in “A House Is Not a Home,” though it isn’t in the show. During the title song, a central couple does what the singer says she longs to do — put her arms around her lover — but they have to do that while threading through the obstacles of chairs. This is choreography that, in the words of the song, says “more than just words could ever say.”

“They’re all tragedy songs, and they’re all upbeat and kind of hopeful,” Morris said. “Rhythmically and harmonically, they’re thrilling.” The message, he added, is: You treated me bad as usual, “so goodbye, but I love you, question mark.’”

“I’ve had despair,” Morris also said, but now he was talking not about Bacharach’s songs but about the process of creating a dance during a pandemic. During the year he has been working on “The Look of Love,” he said, he has had “maybe three or four rehearsals with the full complement of the 10 people cast in the piece.” Dancers missing rehearsals because they had COVID, the need to teach replacement dancers and then loop in the original dancers, the daily COVID tests: “It’s been tremendously difficult,” he said, on top of rehearsing rescheduled performances of “Pepperland” and other large works under the same uncertain conditions.

“I’ve had dancers new to me dancing in pieces they had never seen,” Morris said. “They did great. But that’s luck.”

I was tempted to make a joke about the Blob or about “What the World Needs Now,” another song in the show. But I didn’t, and Morris grew sanguine about a dance he hadn’t yet finished.

“I’m semi-confident it will be wonderful,” he said. “The music’s going to be fabulous. It won’t be boring.”

“And it’s about time we get to put on another show,” he added. “Everybody’s getting teary already.”

This article originally appeared in The New York Times.