"I have a bunch of material that I'd written over the last 11 years that I only perform for the troops," Keith explained in an interview Tuesday morning (May 20) with CBS Chicago's US99.5. "They're little funny songs, but some of them are kinda dirty, and some of them are locker room. And I didn't really have any venue to play them at over here [on U.S. shores]."

Keith said that the producers already knew they wanted him to perform his hit "American Soldier" with members of the military. But, he said, they told him that they also wanted him to bring out one of the songs from his USO tours.

"I got a song called 'Call a Marine.' It's kinda dirty, but�they said, 'if you clean it up just a little bit, we'll let you do it, and we want you to do it with this Marine.'" The Marine in question turned out to be Lt. Col. Mike Corrado.

"And he killed it, man," Keith said about the performance. "I sang the verses, and then this guy took over and sang the choruses." The show was taped last month in Las Vegas, and it airs tonight (May 20) at 9pm ET/PT on CBS.

The whole idea behind songs like "Call a Marine," Keith explained, was to create an experience for the troops that was unique and special to their experiences. "They already know 'I Love This Bar' and 'Beer for My Horses' and 'Shoulda Been a Cowboy,'" he said. "But let's do something that's written specifically for them."

For instance, he brings up a song called "Ballad of Balad" that he says "is about an Army recruiter lying" to a new potential recruit. "He's telling him, 'You're going to see the world, you're going to get a job and a trade.' And then first day over there he's in combat. 'You never told me I'd get my tail shot at!'"