John Marshall (born 4 January 1962) is an American musician. He is the former guitarist for the thrash metal band Metal Church (1986–1996, 1998–2001). He was the guitar tech for Metallica's lead guitarist Kirk Hammett. Marshall also became the fill-in rhythm guitarist for Metallica's James Hetfield in two occasions when Hetfield was injured. First in 1986 (while still performing his duties as guitar tech) while Hetfield's wrist was broken due to a skateboarding accident, and again in 1992 when Hetfield was recovering from pyrotechnics burn injuries stemming from a concert with Guns N' Roses in Montreal during the Guns N' Roses/Metallica Stadium Tour. Marshall joined the band onstage for a performance of Sad But True during Metallica's four-day 30th anniversary concert in December 2011 at t