Bill Church was the bassist on the first Montrose album. He was replaced in Montrose by Alan Fitzgerald. He later played with former Montrose singer Sammy Hagar as a solo artist. Montrose was the original Californian hard rock band, pioneering the kind of short and punchy songs that would be a template for later and more successful bands such as Van Halen. ... Samuel Roy Hagar (born October 13, 1947), better known as Sammy Hagar, is a U.S. rock guitarist, singer, and composer. ...