More songs, more stars, more fun! Michael Buble helps Elmo to "Believe in Yourself" while Gwen Stefani explains how to "Be a Good Friend". Oscar is joined by Macklemore to sing about his love of trash, and there's music everywhere when Fifth Harmony stops by. Australian sensation Jessica Mauboy has kids hopping with "Five Kangaroos," OK Go paints a picture of the "Three Primary Colors" in amazing stop motion, and Elmo rocks out with Rev Run while learning to "Hop This Way". (thetvdb.com)