The song was written by David Paich, who has said that the song is based on numerous girls he had known. As a joke, the band members initially played along with the common assumption that the song was based on Rosanna Arquette, who was dating Toto keyboard player Steve Porcaro at the time and coincidentally had the same name. Arquette herself played along with the joke, commenting in an interview that the song was about "my showing up at 4 a.m., bringing them juice and beer at their sessions." In the verses, the key is changed from G major to F major, accompanied on the original recording by the lead vocalist changing from Steve Lukather to Bobby Kimball.