The system and how it works
A Hindi film song exists in two stages. First, the music director — the composer — records the track in a studio, often before shooting begins. Trained playback singers perform the vocals; their voices are finalised, mixed and locked. Then the picturised sequence is shot on set or on location, with the actor miming to the pre-recorded track through a monitor or earpiece. What reaches the audience is a seamless join between a voice that was never on set and a body that never sang a note.
The term for this is playback singing, and the singer is called the playback singer. The credit appears on screen and on the soundtrack release: not just the composer and lyricist but the singer, named, for each song. In the classical studio era, a handful of voices dominated enormous volumes of work. Lata Mangeshkar and her sister Asha Bhosle between them sang for most of the leading actresses of their generation; Mohammed Rafi, Kishore Kumar and Mukesh were the dominant male voices. Their names, not the actors', are how a Hindi film song is remembered and searched.
The 1978 Don and its singers
The 1978 Don, directed by Chandra Barot and produced by Nariman Irani under the banner of Nariman Films, has a score by Kalyanji-Anandji — the composer duo of brothers Kalyanji and Anandji Shah — with lyrics by Indeevar. The playback cast is near-canonical for the period. Kishore Kumar sings the title song and "Khaike Paan Banaraswala," among others; his elastic, often comic phrasing fits the dual nature of the hero, who is by turns a street performer and a feared criminal. Asha Bhosle and Lata Mangeshkar both appear on the soundtrack. The title song itself, "Don," is Kishore Kumar's, and its buoyancy sits deliberately against the menace the character is supposed to project — a tension the picturisation of that sequence makes visible.
The actor on screen for most of these songs is Amitabh Bachchan, playing both the gangster Don and his lookalike Vijay. The separation between voice and face is so normalised by this point in Hindi film history that audiences read the performer's physicality, not the vocal quality, as the character's signature. Bachchan's posture, timing and expression carry the performance; Kishore Kumar's voice provides its emotional register.
The 2006 remake and its approach to the same material
Farhan Akhtar's remake, produced by Excel Entertainment, assigns the score to Shankar-Ehsaan-Loy and the lyrics primarily to Javed Akhtar. The playback choices reflect a changed sonic world: the arrangements move toward contemporary production, with electronic textures and a more compressed dynamic range. Several songs from the original are remade — the title song reappears with new orchestration — and reusing a melody carries its own set of decisions about how much the voice and the arrangement can change before a song stops being the same song.
Udit Narayan and Shankar Mahadevan contribute male vocals; Sunidhi Chauhan and Shreya Ghoshal appear on the female side. Shah Rukh Khan, playing Don in the remake, brings different physical grammar to the mimed sequences — more angular, cooler in register — and the singers chosen largely match that shift in temperature.
Why the credit matters
The playback system means that discussing a film's music requires holding two sets of names at once: the faces associated with the songs in memory, and the voices that made them. In both versions of Don, the singers are not incidental technicians — they shape the character as much as the costume or the lighting does. When Kishore Kumar shades a lyric with irony, that irony is in the film. When a 2006 arrangement strips that irony for sleekness, the character has changed, even if the words are identical. Crediting the singer is not a formality. It is an acknowledgement that in Hindi cinema, the voice is a creative instrument, and the playback singer is, in that precise and literal sense, the character's other half.