Hold the obit - we're alive and rocking says Grateful Dead's John Mayer

From left, the Grateful Dead's John Mayer, Bill Kreutzmann, Mickey Hart and Bob Weir hold court at a California music studio (AP)

Singer-songwriter John Mayer has proudly declared himself a "Deadhead", defending members of the Grateful Dead's decision to regroup after playing what was supposed to be the band's final tour this summer.

Mayer is rehearsing in a city north of San Francisco with three of the four remaining members of the rock band for an autumn tour that kicks off on October 29 in New York, months after the Dead played to devoted fans who, in some cases, paid thousands of dollars for sold-out shows in the San Francisco Bay Area and Chicago.