made a guest appearance on Mark Tremonti's guitar instructional DVD The Sound & the Story, to which Kennedy provided an in-depth lesson on how to play his guitar solo on the Alter Bridge song "Blackbird". In 2009, he appeared on Slash's self-titled album, co-writing and singing lead vocals on the songs "Back from Cali" and "Starlight". In addition, he has made live appearances with Sevendust and Gov't Mule. In 2011 it was announced that he will appear on a planned tribute album to Tommy Bolin. Further details were announced in January 2012 that the album would be called Great Gypsy Soul. It was released on March 27, 2012, on 429 Records, and Kennedy appeared on a song called "Dreamer" with Nels Cline of Wilco. Other contributors include Steve Lukather, Joe Bonamassa, Peter Frampton, and Glenn Hughes. In 2016, he collaborated with rapper Darryl McDaniels and Disturbed bassist John Moyer on the song "Flames". Also in 2016, he sang on "Black & White" on the Richards/Crane debut album, World Stands Still. Artistry and influences Kennedy is influenced by a wide range of artists of several genres. His earliest influence was Led Zeppelin, although he drew his singing influences from jazz, blues, rhythm and blues, and soul artists when he discovered Stevie Wonder and Marvin Gaye albums in his parents' record collection. He said that he owned Stevie Wonder's 1982 compilation album Stevie Wonder's Original Musiquarium I, which was one of his earliest inspirations as a singer. From there, he discovered Songs in the Key of Life, which he has since stated is one of his favorite albums, and today cites Stevie Wonder as a major influence on his singing. He has also cited other jazz players and soul singers John Coltrane, Al Green, Mike Stern, Miles Davis, Otis Redding, Frank Gambale, Pat Metheny, Lyle Mays, and Curtis Mayfield as early influences. He also loves blues music. Additional influences include Guns N' Roses, U2, AC/DC, Mastodon, and Radiohead. Singing style Kennedy's favorite singers include Jeff Buckley, Robert Plant, Bon Scott, Chris Whitley, and k.d. lang. He has stated on several occasions that Jeff Buckley was, and is, a major influence on him as a singer. When asked to describe his vocal style, he said, "I wanted to fuse together my favorite elements of rock and soul singers into something I could call my own. The inflections of Stevie Wonder with the soaring