Watch Stephen Colbert Do His Best Toby Keith Impersonation

New 'Late Show' host dons cowboy hat and denim to sing "Ain't As Good As I Once Was" during last night's Songwriters Hall of Fame induction

During last night's Songwriters Hall of Fame induction ceremony in New York, honoree Toby Keith was saluted by a surprise guest: Stephen Colbert. The host of CBS's Late Show wasn't listed in the evening's program and didn't walk the preshow red carpet, so his appearance was just as unexpected as whom he was inducting.

"'Why the hell is Stephen Colbert honoring Toby Keith?'" he acknowledged in his remarks. As it turns out, Keith inspired the irreverent comedian and host when he appeared as a guest during the early days of his Comedy Central series The Colbert Report.

"He was leaving out the stage door and I was going to the rewrite room. This was very early on in my show and he didn't know what he was in for, I guess," Colbert continued. "He turned around to me and he said, 'Hey man, you do a great job — whatever the fuck it is you do.'"

Colbert was so tickled by the comment that his producer had it stitched on a pillow for him as a gift, which he brought onstage to display. Following the introduction, Keith performed the title track to his 2011 album Clancy's Tavern and said the Songwriters Hall of Fame honor was the "only thing I ever wanted."

"I don’t know if people know that I wrote all that stuff, but I outworked everybody," Keith told ABC Radio earlier. "I put a[n] album out every year, I wrote 99 percent of it and this is the reward you get. And this is the only award I ever wanted."

Keith wasn't the only artist representing Nashville at the event, which also inducted Bobby Braddock, Willie Dixon, Robert Hunter and Jerry Garcia, Cyndi Lauper and Linda Perry, and presented special awards to Van Morrison, Lada Gaga, John LoFrumento and Nate Ruess.

For the induction of Grateful Dead lyricist Robert Hunter, Zac Brown took the stage to perform "Casey Jones." (Watch the video below.) "The legacy of the Dead is tremendous," Brown told the AP on the red carpet. "How many people they took care of for so long, which I have a tremendous amount of respect for, and try to follow in those footsteps and try to have the freedom and the following that they've instilled in the culture."

Jennifer Nettles was also in attendance, honoring Bobby Braddock, the songwriter behind George Jones' signature song "He Stopped Loving Her Today," with a performance of the country classic.