While we all eagerly await the new Muppets show and the impending deluge of great celebrity cameos it’ll provide, this can tide us over for a bit: That velvet-voiced crooner Josh Groban joined Jim Henson’s beloved characters for a lovely rendition of “Pure Imagination,” the song made famous by Gene Wilder in Willy Wonka & the Chocolate Factory. Lindsey Stirling provides the strings, to Miss Piggy’s chagrin.