Brian Andrew Leiser (better known as Fast, born 1972), is a member of the band Fun Lovin' Criminals,[1] plays bass, keyboards, harmonica, and the trumpet. He attended Horace Greeley High School in Chappaqua NY, graduating in 1990.

Brian's nickname (and stagename) is "Fast", which was given to him while attending Syracuse University. The name "Fast" is a shortened version of the nickname "Fastman" -- a reference to the speed at which he often spoke.

Brian's start in popular music was as a keyboardist and backup singer for the Westchester, New York, 1980s synthpop group, Departure. He moved on in the early 1990s to become the frontman for the electrodance band Mosesonacid, which appeared in the 1995 film Vibrations but was dismantled once Fun Lovin' Criminals began to garner greater local recognition.

Fun Lovin' Criminals has enjoyed particular success in Europe but has performed globally. The band's music has been known worldwide.

Brian has finished working on the Fun Lovin' Criminals sixth studio album, Classic Fantastic, which was released 1 March 2010, and has received impressive reviews among fans. On the album, Brian features a short rapping section in the song, "We, the Three", and provides backing vocals on others.