"I said, 'You need to get the fuck back together again soon, because we all miss you,'" says Aerosmith singer
Eric Church, Brandon Flowers, Tom Morello, Sheryl Crow and others also set to perform
'Pieces of You' singer rocks out to "Whole Lotta Love" in Phoenix
Industrial metal group's first U.S. performance in a decade centerpiece of 2-DVD set
"I think country is the new rock & roll â€” everyone is trying to stretch out"
Seven-minute funk blues worked up from concert jam