If Warren Zevon were still alive, you'd certainly have seen him on Letterman's farewell tour.
Zevon was one of Letterman's favorite musicians and even filled in for Paul Shaffer as bandleader when he was on vacation.
When Zevon received a diagnosis of terminal lung cancer, Letterman turned an entire hour over to his friend for conversation and music.
"Enjoy every sandwich," Zevon advised, as good parting words.
Watch highlights from the music and conversation below.
"Enjoy every sandwich": Zevon discusses his lung cancer diagnosis
"Roland the Headless Thompson Gunner"