"Sunday (The Day Before My Birthday)" is a song by American electronica musician Moby, released as the fifth single from his 2002 studio album 18. It was released in the UK as a single on February 24, 2003. It features a sample of Sugarhill Records founder Sylvia Robinson's song "Sunday".
The song should not be confused with another Moby song called "Sunday", featured on Play: The B Sides.
The video for the song features the small aliens from the "In This World" music video going back to Earth, this time being recognized on the Hollywood Walk of Fame. They become renowned celebrities and enjoy major success, including a television series. The end of the video shows the aliens piloting their spacecraft back to their much less stressful home planet.