During the course of the film, the character played by Shahrukh Khan passes through each of the 7 shades of love defined in ancient Arabic literature - attraction, infatuation, love, reverence, worship, obsession and death.
For the song "Jiya Jale, Jaan Chale," singer Lata Mangeshkar had some problems singing in the higher octaves due to her age, so composer A.R. Rahman kept her voice as low as possible.
Dil Se Re song Bass Guitar was played by Guy Pratt - Pink Floyd Bass Guitarist - post Roger Waters era.
The film's first song, "Chal Chaiyya Chaiyya", is also the opening song of the Hollywood movie Inside Man : L'Homme de l'intérieur (2006) starring Denzel Washington and Clive Owen.
Shah Rukh Khan did not use a safety harness while the filming the sequence aboard the moving train for the song "Chal Chaiyya Chaiyya."