Plus: Hear Oberst's original "LAX" demo.

In order to portray a prolific singer-songwriter in the upcoming music-tinged romantic comedy Juliet, Naked, star Ethan Hawke was treated to the penmanship of some of indie rock’s finest.

In the first release from the album’s soundtrack, premiering exclusively via Billboard, Hawke approaches a demo of one of the film’s centerpiece tracks “LAX,” provided by Bright Eyes’ Conor Oberst. Though the original iteration brings the emotional core of the lyrics into focus, the final version reveals Hawke completely immersed in his rock-star persona, with a gripping full band production and fleshed-out studio sheen.

Producer Nathan Larson provides insight to the song's journey, telling Billboard, "Conor had demoed this as a ballad on piano, and we recorded something in this slower contemplative style for the film. But in the final recording session, it was Ethan who had a burst of inspiration and pushed the band to track 'LAX' as a rave-up punky thing, which is the version actually heard in the movie."

"The greatest challenge on a project where music looms so large is to create songs that feel real, and elicit performances that enhance this authenticity," Larson cautions. "To the extent that we succeeded in this effort, I credit Ethan's complete commitment to the music, his insistence on pushing himself as a vocalist....and equally the excellent material like Conor's 'LAX.'"

“LAX” is one of several collaborations for the film, including original compositions by Ryan Adams, M. Ward and Robyn Hitchcock. Juliet, Naked, based on a 2009 novel by Nick Hornby, stars Rose Byrne and Chris O’Dowd, as well as Hawke as the enigmatic artist Tucker Crowe.

The soundtrack is set to release the same day as the film, on Friday via Milan Records.

Check out Oberst's demo as well as the film version of “LAX” below.