Kristian Bush is known for writing hit country songs, but now, he's putting on a different musical hat, as the composer of the new play Troubadour. 

Troubadour is a romantic comedy set in the 1950s, about a group of friends who, paired with their unconventional style, manage to change the course of country music. Playwright Janece Shaffer says the inspiration for the play came after a trip to Nashville's Country Music Hall of Fame, where she saw an exhibit on costuming and fell in love with the time period of the 1950s. Country music of the era was dominated by stars such as Nudie Cohn, Johnny Cash and Hank Snow.

"It just got me so excited, and I just kind of fell into Nashville in 1951, and I started hearing voices when I was going to sleep," Shaffer says, calling the decade a "moment of change." "People told me, 'You need to write about this.'"

When she was looking for the right person to compose the music for Troubadour, an acquaintance recommended Bush, and after the two met for breakfast and got lost in conversation for hours on end, they knew the partnership was brought together by fate.

"You speak the way I speak," Bush says of Shaffer's writing. "The story was so compelling, and the conversation was so entertaining."

Bush wrote 16 original songs for Troubadour. While it was a new experience for the country star, he says it wasn't much of a diversion from his career as a hitmaker.

"The experience isn't very different than what I've been doing for 20 years," Bush admits during an interview at his Nashville home. "If you're writing songs for Jennifer Nettles to sing, it's not very different than writing songs for someone else onstage that acts and is emotionalizing the things you're writing."

The Sugarland member has managed to create a body of songs that sound like they could've been written in the 1950s, from the classic "Troubadour" to the haunting "Magnolia Wind" and even the quirky "Ice Cream and Lollipops." To bring these characters to life through song, Bush says he got inside their heads and "quizzed" Shaffer on their backstories to get a feel for who they are.

"I know I wrote the songs based on her characters, but what I'm now figuring out is she['s] starting to change what they say based on the songs," Bush says about the back and forth that occurred between Shaffer and himself while composing the music. "And so now, they all belong together, they don't function independently of each other anymore."

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One member of Troubadour's cast is Radney Foster, a singer-songwriter turned actor who plays the character of Billy, a father and musician, who sings the show's title track.

"I called Kristian, and I said, 'You wrote my life,'" Foster says of his reaction to "Troubadour," calling it his favorite song "because it is so real to me personally."

What drew Foster to the role, and the song, was his connection to the character, who's facing the end of his career and hoping his music has a lasting impact. Foster spent many years in the country music duo Foster & Lloyd, which saw success in the '80s. He's since broken off into a solo career, garnering cuts by Keith Urban, Gary Allan, Sara Evans and more.

"Here is this character who's going to stand on a stage, and he realizes at the end of his career, 'If I'm really lucky, they're going to remember a song.' And I thought, 'I gotta play that; please let me be that guy,'" Foster says.

According to Bush, though Troubadour is set in a time period more than 60 years ago, the story is one that still rings true today.

"I think these fit in the country music cannon now because there are so many more kids making music than ever before, and country music is in the hands of the youth at all times; it's never in the hands of the aged," he says. "They've already been the youth, and they're carrying the torch to keep everyone floating, but it's always the youth that pulls it ahead, and it's going on in the story. It's kind of testimony to exactly what's happening right now."

Fans can hear the new music created by Bush as Troubadour continues to play at the Alliance Theatre in Atlanta, Ga., through Feb. 12. His new single, "Sing Along," is also available for download.

Listen to Kristian Bush, "Sing Along"