John Mayer will join the Zac Brown Band on stage during the Southern Ground Music & Food Festival in Charleston, SC. The festival, which is put on by the Zac Brown Band, will take place October 20-21 at Blackbaud Stadium on Daniel Island. In addition to the music, festivalgoers will be treated to concessions from “Cookie,” Zac Brown Band’s tractor-trailer sized mobile kitchen, which will offer items prepared using Zac Brown’s recipes, as well as selections from local Charleston restaurants. The Avett Brothers, Grace Potter & The Nocturnals, Michael Franti & Spearhead, The Wailers, JJ Grey & Mofro, The Charlie Daniels Band and many more will also be performing at the festival.