The other day the Coterie Theatre had the feel of an old Hollywood soundstage.

In a room backstage Harry Connick Jr. was writing new music on an electronic keyboard hooked to his laptop and cueing printouts for musical director Molly Jessup, who was at an upright piano in the theater leading a cast through the material as soon as it came off the printer.

Connick, his producer Scott Landis and book-writer Andrew Fishman were in Kansas City to workshop “The Happy Elf,” a holiday-themed musical that will receive its world premiere at the Coterie in November. The piece first saw life as an animated TV movie in 2005, but the Coterie’s artistic director, Jeff Church, thought it could work as a stage show.

But the whole enterprise, Connick explained, began with one little song about the most enthusiastic of Santa’s elves.

“I had written a song called ‘The Happy Elf’ that (Scott) thought would translate well into a sort of children’s Christmas story,” Connick said. “And Andrew came aboard to write it. So the whole thing spun out of the actual song.”

The tune made its first appearance on “Harry for the Holidays,” Connick’s 2003 holiday album.

“I wanted to do a Christmas CD that had a lot of familiar songs on it, and I wanted to have some new material,” he said. “One was a religious song speaking literally about Christmas. And the others were just secular songs about the whole Santa kind of thing. And this one, the idea just came to me about what’s going on in the workshop, and I’m sure he’s the most enthusiastic of the enthusiastic elves, you know. It came out of that. It was just a matter of sittin’ down and writin’ it.”

Landis said he suggested the possibly of building a show around the song for one simple reason: It embedded itself in his memory bank.

“Honestly, I couldn’t get it out of my mind,” Landis said. “You know, sometimes you hear a song and you go to do your laundry and it keeps banging away in your head. … It was just so fun. It was playful. It reminded me of those animated specials the three of us grew up with, like ‘Rudolph’ and all of those great shows.”

Connick began his career categorized, more or less, as a jazz performer in the Sinatra tradition. In recent years, though, he has moved into another arena — Broadway. He received a Tony nomination for his 2001 musical, “Thou Shalt Not,” and starred in the 2006 revival of “The Pajama Game.”

But Connick said he doesn’t draw big distinctions between different styles of music or different kinds of entertainment.

He played traditional jazz at the start of his career, Connick said, but then moved into more contemporary styles and discovered that a lot of the songs covered by jazz greats actually came from Broadway shows.

“Music is what I’m attracted to,” he said. “All of these great musicians were playing songs that I didn’t really stop to think were part of shows. And probably 90 percent of them were. I mean, Gershwin, Cole Porter. … So I would learn these songs and then find out later they were from shows …

“It’s all the same thing to me,” he said. “Like, when I’m playing a solo on a jazz piece or I’m playing a scene in a film, I don’t feel like there’s much difference between the feeling I get with one or the other.”

Written by Robert Trussell, Theater Critic of the Kansas City Star