Dr. Vaseegaran creates Chitti, a powerful robot in his own image, but it is rejected by the scientific body AIRD due to its lack of human behaviour and emotions. After a lightning strike triggers emotions in Chitti, he begins to develop human-like feelings. However, Chitti falls in love with Dr. Vaseegaran's fiancée, Sana, and turns against his creator, leading to dangerous consequences.
| Actor | Role |
|---|---|
 RajinikanthDr. Vaseegaran / Chitti | Dr. Vaseegaran / Chitti |
 Aishwarya Rai BachchanSana | Sana |
 Danny DenzongpaDr Bohra | Dr Bohra |
 SanthanamSiva | Siva |
 KarunasRavi | Ravi |
 DevadarshiniLatha | Latha |
 Sabu CyrilAgent Shah | Agent Shah |
 Kalabhavan ManiPachaimuthu | Pachaimuthu |
 Cochin HaneefaTraffic Police | Traffic Police |
 RaaghavNeighbourhood Bully | Neighbourhood Bully |
 Boxer DheenaThug | Thug |
 Shriya SharmaCurious Student | Curious Student |
| SSugunthanPolice Inspector | Police Inspector |
 Delhi KumarVaseegaran's Father | Vaseegaran's Father |
| RRevathi SankaranVaseegaran's mother | Vaseegaran's mother |
 Java SundaresanBarber | Barber |
| DDevadasu KanakalaK. Bhajanlal | K. Bhajanlal |
 Rekha SureshNot listed | Not listed |
| SSavitha ReddySana (voice) | Sana (voice) |