FILE - In this May 16, 2015 file photo, guitarist Slash, formerly of the band Guns N&#039; Roses, performs in concert during the MMRBQ Music Festival 2015 in Camden, N.J. Slash made a surprise appearance Friday, July 22, 2016, while the pre-teen band for the musical &quot;School of Rock&quot;was practicing the Guns N’ Roses song “Sweet Child O’ Mine.” (Photo by Owen Sweeney/Invision/AP, File)