John Mayer has spent much of the past six months trying to move past his pop star tag (or at least revise ones definition thereof). After appearing with Buddy Guy and Phil Lesh at the Jammys in April, Mayer joined Herbie Hancocks Headhunters for a brief tour leading up to Bonnaroo in early June. Indeed, during a Bonnaroo press conference, Mayer joked that he is using his celebrity stature to get on as many stages as possible. Last night Mayer moved further into the worlds of jam and jazz, backing John Scofield during his appearance on the Tonight Show with Jay Leno. Mayer appears on Scos forthcoming disc, Thats What I Say, which pays tribute to Ray Charles.