In this film Amitabh Bachchan uses his real family name which is Amit Shrivastav. Bachchan incidentally was adopted by his poet father Harivansh Rai as his pen name through publication.
The makers of this film took elaborate measures to protect the identity of the villain of the film, played by Prem Chopra. Chopra's character communicated with the film's hero, played by Amitabh Bachchan, through phone for most of the film and his lines were dubbed by Kader Khan, who also wrote the film's dialogues. Prem Chopra and Kader Khan were not credited for their acting roles. The film ended with a message to the audience - "Please don't reveal The End.
Kader Khan, who had taken civil engineering classes at the M.H. Saboo Siddik College of Engineering in Bombay before joining films, was credited with the title "Prof." for the dialogues of this film.
Kader Khan dubbed for Prem Chopra.
Amitabh Bachchan acted with Moushumi in only two films, Benaam and Manzil (delayed and released in 1979) which he signed in his early days before gaining his star status. Once he became a popular star he only costarred with top rung heroines - Hema, Rekha, Zeenat, Parveen and Raakhee, and only made an exception for Neetu Singh and Smita Patil in 2-3 movies each. After 1983 he only favored younger heroines like Sridevi, Meenaxi, Jayaprada, Amrita and Rati.