"Twelve Thirty" a.k.a. "Twelve-thirty (Young Girls Are Coming to the Canyon)", the song's main refrain, is a song by The Mamas & the Papas, which was the lead single from the album The Papas & The Mamas. The song peaked at number 20 in the US, but failed to chart in the UK.
The song was written by John Phillips shortly after the band had relocated to Southern California in 1965. It is often cited as the band's last great single. In a 1968 interview, Phillips cited this arrangement as an example of "well arranged two-part harmony moving in opposite directions".
Jim Ward of Rolling Stone, said "Twelve Thirty" was "the last recording of the self-proclaimed 'Golden Era'", he added, "It's probably the best realized song the group has recorded."
The song was inspired by Laurel Canyon, a neighborhood of Los Angeles, California. The song was also inspired by the experience of living in New York City, where a clock on a church steeple, always said Twelve-Thirty. ((And the clock was never fixed). The song fades out during the repeat of the final Chorus.