​Morello teased a special guest for his Defend Minnesota! benefit concert, and after plenty of speculation, The Boss took the stage.

Morello, best known as the guitarist from Rage Against the Machine, also confirmed this last-minute benefit concert on Wednesday. Other performers scheduled to appear at First Avenue in Minneapolis were Rise Against, Al Di Meola and Ike Reilly.

Bruce Springsteen was revealed as the "very special guest" at the First Avenue benefit concert organized by Rage Against The Machine's Tom Morello in Minneapolis Friday.

Both actors pay homage to rock ’n’ roll greats onstage. But their relationships to their muses — and how they perform their songs — are very different.