Last weekend, Gov’t Mule headlined the Cockeysville, MD’s Hot August Blues. During their set, the Mule invited out Warren Haynes Band saxophonist Ron Holloway—who lives in the area—and fellow festival performer Trombone Shorty for a take on “The Letter.” The brass players remained onstage as the band moved into “Feel Like Breaking Up Somebody’s Home.” Then, at the end of the night, Holloway returned for a song that he’s played many times with Warren Haynes Band, “Soulshine.” Gov’t Mule will kick off a Colorado run at Englewood’s Gothic Theatre on September 12.