Watch Ariana Grande perform “imagine” with The Roots on The Tonight Show

Ariana Grande was the musical guest on tonight's episode of The Tonight Show With Jimmy Fallon, performing the second cut from her forthcoming album thank u, next, "imagine." The Roots backed her up, adding some jazzy holiday flourishes and making the first performance of the track a special one. Elsewhere in the episode, Ari stood alongside Fallon, Horatio Sanz, Tracy Morgan and Chris Kattan for a performance of "I Wish It Was Christmas Today," from Saturday Night Live. Check that out below, and watch the "imagine" performance above.