The Late Show with Stephen Colbert Season 2 Johnny Galecki, Chris Matthews, Bash & Pop Season 2, episode 81 Johnny Galecki, Chris Matthews, Bash & Pop January 19, 2017 45 min Actor Johnny Galecki; TV host Chris Matthews; Bash & Pop performs. Previous episode Idina Menzel, Rachel Bloom, Louie Anderson Next episode Jim Gaffigan, Cristela Alonzo, The Avett Brothers