Remember at the end of Camp Rock when the shy, anonymous Mitchie (Demi Lovato) finally gets her Big Moment, singing her song, “This Is Me,†solo — you know, right until her boy-bander love interest (Joe Jonas) makes an impromptu duet out of a self-affirmation anthem with lyrics like, “This is me / I’m exactly where I’m supposed to be / Gonna let the light shine on me� … No? Just us? Well, journey back to 2008, back to a time before “problematic†was en vogue, because Joe made a surprise appearance at Lovato and Nick Jonas’s concert in Washington, D.C., on Tuesday, and a Camp Rock throwback was in order. Joe and Demi delivered a sweet rendition of the earworm-y (if questionable when used as a romantic gesture) tune, melting your Disney Channel Original Movie–loving heart like marshmallows at a campfire. Joe lovingly called the moment “sentimental bullshit.†Dang, who knew Joe wasn’t sacred about those days?