If you love Broadway dance, the revival of “The Pajama Game” – which opened on Thursday at the American Airlines Theatre – is a must-see. That’s because this comedy contains one of the all-time greatest dance numbers in musical theater: “Steam Heat.”

The number is unusual since – unlike most Broadway dance – it can be removed from the context of the show and danced as its own work of choreography. “It does stand on its own,” the director and choreographer of the revival, Kathleen Marshall, said. “Unlike a lot of other musical theater choreography, you don’t need any other information.”

The musical – originally created in 1956 and choreographed by Bob Fosse – concerns the employees of a pajama factory. They’re in a union that is angling for a pay raise. During a union rally, three members get up onstage to present a song-and-dance routine, “Steam Heat,” as the entertainment portion of the rally. The number becomes a show within a show, and gives the characters a reason to dance.

Typically, though, giving characters an excuse for breaking into dance is one of the trickier maneuvers for a choreographer, according to Ms. Marshall, who also created the moves for revivals of “Kiss Me, Kate” and “Wonderful Town.”

“That’s the hardest thing. How do you start the dance? We’re moving, moving a little more, now we’re moving in unison,” Ms. Marshall said, adding that the show within a show opens up more possibilities. “It’s much easier to choreograph when you’re not pretending that you’re not dancing.”

Though Fosse created the original choreography, Ms. Marshall created her own. (When musicals are licensed, only the book and music can be reproduced. The original choreography is usually protected by a separate license.) What she decided to keep was the iconic image of a trio in bowler hats and suits – as well as the flavor of the jazz movements from the era.

“I knew the original choreography. I looked at a lot of other 1950s jazz from television variety shows and movies of the time, as well as Jerome Robbins’s ‘NY Export: Opus Jazz,’ ” Ms. Marshall said.

“There are a lot of turned in knees, contracted backs, and dragging of the feet. Fosse took that and crystallized it into something unique,” she said.

The resulting choreography for the revival is mainly an homage – not a replication. “The number may look Fosse-esque, but that’s because people assume that anyone with a black bowler hat is doing Fosse,” Ms. Marshall said. “The original was almost all in unison and androgenous. It’s precise, very tight, and mechanical.”

Her changes made the dance looser, but she also added a new element that parallels one strain of the plot. In this version, the woman dancing in “Steam Heat” also plays a mousy character who blossoms throughout the story. In the first act, she’s the factory tomboy, but she finds love and becomes more feminine. When “Steam Heat” starts, she’s in a baggy suit and bowler hat, but by the end, she wows the crowd in a corset.

The sexiness adds to the idea of “heat,” which originally was more about getting the group riled up to demand the wage increase.

Among the original lyrics: “Come on union, get hot!” It’s also worth noting that “Steam Heat” has some delightful rhyming lyrics by Richard Adler:

The radiator’s hissing,
But still I need your kissin’,
To keep me from freezin’ each night.
I got a hot water bottle,
But nothing I got’ll,
Take the place of you, holdin’ me tight

Though “Steam Heat” gives the characters free rein to dance, there’s still the niggling little detail that these dancers are, within the story, factory workers. “You do have to suspend disbelief. Let’s face it: If they could dance like this, they wouldn’t be staying in Cedar Rapids,” Ms. Marshall said.

The additional dancing in “The Pajama Game” takes place at the company picnic and in a speakeasy called Hernando’s Hideaway. The later scene allows the characters to dance because they’re at a nightclub, and Fosse’s original Broadway choreography was cut down for the 1957 movie version (starring Doris Day). Ms. Marshall’s rendition allows the characters to stay within their respective identities, but to loosen up a bit because they’re out on the town.

“You want to feel like these are real, blue-collar people. They’re at the picnic or Hernando’s Hideaway. It gives them a chance to move more than they would in real life,” Ms. Marshall said.

“They’re the same character, but they change from having a tool box in hand to a martini glass.”

Ah, yes, but these “real, blue-collar people” happen to include the hunky crooner Harry Connick Jr., who stars as Sid Sorokin, the new superintendent of the factory. He’s management, but he falls in love with the pretty girl who’s the head of the union, Babe Williams, played here by Kelli O’Hara (who recently starred in “A Light In the Piazza”). Can Mr. Connick dance? Ms. Marshall says yes – and if that’s true, he’ll be one mean triple threat.