The song was released on 15 January 1999 as the lead single from their debut album Europop.
The song is the group's most popular single, reaching number one in many countries such as Ireland, the United Kingdom, the Netherlands, France, Sweden, Switzerland, New Zealand, Finland, Norway, Australia, and Germany.
In the United Kingdom, the song originally entered the top 40 purely on import sales. It was only the third single to do this.
The song received a Grammy Award nomination for Best Dance Recording at the 2001 Grammy Awards.
"Blue", written by Eiffel 65 lead singer Jeffrey Jey, keyboardist Maurizio Lobina, and producer Massimo Gabutti, was inspired by group member Maurizio Lobina's composed opening piano hook.