Mr. Big is a hard rock group that formed in 1988. The band is a quartet composed of Eric Martin (vocals), Paul Gilbert (guitar), Billy Sheehan (bass), and Pat Torpey (drums); Mr Big also included Richie Kotzen, a reputable blues-based guitarist who replaced Gilbert in 1999. The band is noted especially for their musicianship, and scored a number of hits. Their songs were often marked by strong vocals and vocal harmonies. Their hits include "To Be With You" (Billboard Hot 100 number one single in 15 countries for weeks, in 1991) and "Green-Tinted Sixties Mind".