Bruce Springsteen and U2 will not perform at the concert, though organizers had previously announced they would (see "U2, Bruce Springsteen, Willie Nelson Set For Johnny Cash Tribute Concert"), but Sheryl Crow, Wyclef Jean, Dave Matthews and Chris Isaak have been tapped to perform cover tunes from Cash's five decade long career.

No specific explanations have been made about the Boss' and U2's decision to opt out of the tribute, but it is believed that Springsteen's camp was concerned about scheduling issues related to the April 9 launch of his world tour in Spain, while U2 is in the midst of recording a new album with producer Daniel Lanois.

Other artists coming out to fete music's original "Man in Black" include the Mavericks, Lyle Lovett, Cash's Highwaymen bandmates: Willie Nelson and Kris Kristofferson, and Cash's daughter, Roseanne.