All were shocked last night when Elvis Costello and The Roots performed together on the Jimmy Fallon Show.  Well, not exactly.  You see the artists actually recorded their new joint-album Wise Up Ghost in The Roots’ dressing room in the Fallon studio.  Watch below as Costello and The Roots soundly strutted the best song off the new album, Walk Us Uptown, augmented by a horn section of four.  After, check out their web-only rendering (with added female vocalist) of the slow-ful Tripwire, with nursery-piano sounds leading into a superb group vocal.  At bottom watch Costello’s interview with Fallon in which Elvis explained how The Roots collaboration came about.  Superb stuff.  Costello will again appear on the Fallon Show on Thursday.