Green Day are big fans of The Late Show, and host Stephen Colbert is a big fan of Green Day. So while chatting about their mutual love for each other, Colbert asked if he could sing his favorite song, "Good Riddance (Time of Your Life)," with the band.
But after being told that singing the lyrics would cost him a lot of money, he created a new segment called, "Lyrics We Can Afford to Songs We Love." Basically, he replaces the lyrics with ones found in the public domain. In this case, he chose "Camptown Races."