New Zealand duo Flight of the Conchords performed a new track, “Father and Son,” Monday night on The Late Show With Stephen Colbert. The group, Jemaine Clement and Bret McKenzie, were promoting their upcoming HBO special Flight of the Conchords: Live at the London Apollo, which will air October 6th. The performance marked a return for the duo, whose HBO series ran for two seasons in 2008 and 2009.