Professor Parimal Tripathi (Dharmendra) is a botany professor who falls in love with Sulekha Chaturvedi (Sharmila Tagore) during a women's college botany excursion. Prof. Parimal Tripathi helps the bungalow watchman to get to his village downhill to enable him to see his grandson who's fallen ill. Meanwhile, he disguises himself as the bungalow watchman to protect the old man's job. Sulekha finds out one day about the cover-up and is charmed on seeing Parimal's real personality. They both get married. Parimal loves playing pranks and is the antithesis of regular professors. Sulekha, on the other hand is in awe of her jijaji (brother-in-law) Raghavendra (Om Prakash). She considers her jijaji to be highly intellectual and looks upon him as her idol. Parimal develops an inferiority complex thanks to Sulekha's excessive praise of her jijaji and decides to prove that he is in no way a lesser mortal. Jijaji, meanwhile, has written a letter to Haripad bhaiyya (David Abraham Cheulkar) asking him to send a driver who can speak good Hindi because his present driver James D'costa (Keshto Mukherjee) uses improper dialect. This provides the perfect opportunity for Parimal to get to see and interact with jijaji. Parimal becomes Pyare Mohan Ilahabadi, a motor-mouth driver who pretends to hate the English language and so speaks only Hindi. So begins the comedy of errors, as Parimal and Sulekha play prank after prank on the unsuspecting jijaji.

First they pretend that Sulekha is not happy with her new marriage, then they put across the impression that Sulekha is having an affair with Pyare Mohan, and if that was not enough, they get Parimal’s long-time friend Sukumar Sinha (Amitabh Bachchan), a professor of English literature, to temporarily act as Parimal and portray him as a serious and boring lecturer, the complete opposite of Parimal's character. Pyare Mohan's excessively refined Hindi, his habit of correcting Jijaji's usage of the language and his persistence in getting jijaji to teach him English all serve to irk Jijaji to no end and provide for many laughs. Parimal's long-time friend P K Srivastava (Asrani) is also party to the prank. His sister-in-law Vasudha (Jaya Bachchan) suspects fake 'Parimal' - Sukumar Sinha - of infidelity to his wife 'Sulekha' when he tries to get close to her. Sukumar falls in love with Vasudha who at first believed he was Parimal, but Sukumar reveals to her the real drama behind all this mix-up of situations. Lata Srivastava (Lily Chakravarty), P K Srivastava's wife, is also angered over the latest 'extra-marital' love affair. But toward the end, Sukumar and Vasudha end up marrying in a temple where Haripat Bhaiyya coerces Pyare Mohan to 'kill' himself so that Parimal could surface. Thus jijaji comes to comprehend the whole enactment, finally admitting that he was truly fooled. The film revolves around the resolution of these funny mishaps.

• Dharmendra as Dr Parimal Tripathi / Pyare Mohan Allahbadi
• Sharmila Tagore as Sulekha Chaturvedi
• Amitabh Bachchan as Professor Sukumar Sinha
• Jaya Bachchan as Vasudha Kumar
• Om Prakash as Raghavendra Sharma
• Lily Chakravarty as Lata Kumar Srivastav
• Asrani as Prashant Kumar Srivastav
• David as Haripad Chaturvedi
• Keshto Mukherjee as James D'Costa, Driver
• Usha Kiran as Sumitra Sharma
• Master Bittu as Ratna
• Aarti
• Amol Sen
• Chaitali
• Dev Kishan
• Lalita Sinha
• Naina Apte
• Masterjee

• Director - Hrishikesh Mukherjee
• Producer - Hrishikesh Mukherjee, N. C. Sippy, Romu N. Sippy
• Presenter - N. C. Sippy
• Story - Upendranath Gangopadhyay (Bengali story Chhadobeshi)
• Screenplay - D. N. Mukherjee, Gulzar
• Dialogue - Biren Tripathi, Shakeel Chandra, Gulzar
• Cinematographer - Jaywant Pathare
• Editor - Subhash Gupta, Pandit Sridhar Mishra
• Art Director - Ajit Banerjee
• Costumes Designer - Meena R. Sippy

All lyrics written by Anand Bakshi; all music composed by S. D. Burman^[5].

This film is one of two released in 1975 to cast Dharmendra and Amitabh together, the other being Sholay. Apart from these, Ram Balram was the only other film that the two starred in together, if one does not count Dharmendra's guest appearances in Andha Kanoon and Naseeb, and Amitabh's cameo in Guddi, Dost and Soorma Bhopali. They had a guest appearance in the 2003 movie Hum Kaun Hai?, also dubbed in Bengali, as well as in the 1977 movie Charandas.

• According to film expert Rajesh Subramanian, some of the scenes were shot at producer N C Sippy's bungalow at Juhu. The bungalow today belongs to Amitabh Bachchan and is named Jalsa.
• Jaya Bhaduri was pregnant during the making of the film. Most of her shots have been taken very carefully, as to avoid her profile view.
• Mohammed Rafi has one stanza less in the song "Sa Re Ga Ma", as he was not present during the dubbing session. Kishore Kumar, who was the other singer, sang the additional stanza.
• Hrishikesh Mukherjee wanted newcomers for the parts played by Amitabh Bachchan and Jaya Bhaduri.
• Viewing a solar eclipse with the naked eye causes damage to the eyes. During the February solar eclipse of 1980 the Indian government broadcast Chupke Chupke during the eclipse on India's state broadcaster Doordarshan to encourage people to stay inside and not venture out and look at the eclipse with the naked eye.

Numerous DVD editions entered the market by companies like "Digital Entertainment inc.", "Shemaroo Entertainment" and "Eagle Home Video". These were released as non-restored, non re-mastered editions and bare bones, void of supplementary features.

Eagle Home Video came out with a restored edition of this movie, preserving the original aspect ratio in 4:3 pillar box and a DTS Master Audio (HD) in 2.0. The restoration took place in Shemaroo studios.