There's no doubt that pairing a band with a full orchestra offers fans a unique way of seeing their favorite act in concert. But the experience doesn't come without challenges, as Bright Eyes band member Nate Walcott has recently learned.

When the Omaha, Neb.-based indie rock band steps onstage Saturday (Sept. 29) to perform alongside the Los Angeles Philharmonic at the Hollywood Bowl, countless hours of grueling work for Walcott will have finally paid off. Not only has the multi-instrumentalist been touring nonstop behind Bright Eyes' April release, "Cassadaga," but he's also spent the past eight months writing the approximately 60-piece orchestral score for the show at the 17,300-seat venue.

"It was the biggest project I've ever worked on as far as arranging is concerned," Walcott tells Billboard.com. "It's almost music math."

Without giving away too many details, Walcott says the set list for the show will comprise songs from the past eight years, many of which contain orchestral elements. "In some cases I would take existing melodies or parts, and score them for a full orchestra," he explains. "In other cases, I composed whole new elements -- melodies, harmonies, whatever."

But arranging rock songs for "40 strings, 11 brass and 12 woodwinds" didn't happen overnight. The biggest obstacle, Walcott observes, was working on the project while touring with Bright Eyes. "It's hard to do anything on tour, let alone put together 15 arrangements for the Los Angeles Philharmonic," he says.

There are no orchestral concerts scheduled for Bright Eyes beyond the Hollywood Bowl date, but Walcott says he wouldn't be surprised if other shows sprouted up at a later date. With the score edited and printed, Bright Eyes "could conceivably, with very little preparation, do a show with any orchestra around the world," he says. "These orchestras don't rehearse. They just show up and read it."

The upcoming concert will feature support from Yo La Tengo and M. Ward, both of whom will perform in their usual incarnations.