Saturday Mash-Up Live!: Season 7, Episode 4

7 - 4: The Next Step and ThatsWatson

Alexandra Chave - aka Piper in The Next Step - struts into the Mash-Up studio. Online star ThatsWatson takes on the Mash Car Rally, and there is a high-octane Joe v Shereen challenge. Plus cartoon fun in Pokemon, and somebody will be slimed!