Singer/songwriter John Mayer will join the The Rolling Stones at the group's New Jersey show in Newark on Thursday night - but don't expect him to sing.

Katy Perry's rumored boyfriend was silenced by vocal problems last year and he's still resting his voice - but that isn't going to prevent the guitarist from hitting the stage with the rock legends.

The gig was the first of two Stones 50 and Counting shows at the Prudential Center; Lady Gaga, Bruce Springsteen and The Black Keys are set to join Mick Jagger and his bandmates onstage on Saturday, when they close their brief run of shows with a concert that fans will be able to watch live via select pay-per-view cable channels.

Eric Clapton and Florence Welch joined them for a 50th anniversary show in London and Mary J. Blige and Gary Clark Jr. joined the group for a recent gig in Brooklyn, New York.

The Stones and Clapton were part of Wednesday night's 12-12-12 The Concert for Sandy Relief benefit show in the Big Apple.