1 The inspiration
The plot of the film was inspired from Mother India. A tale of a mother caught between two sons on opposite sides of the law. Amitabh played a character based on Sunil Dutt's Birju in Mother India.
2 The beginning of Kabhie Kabhie
While working on the sets of Deewar, Yash Chopra was also working on a love story based on the poet Sahir Ludhianvi's life. This turned out to be the film 'Kabhi Kabhie'.
3 Amitabh's style statement
Amitabh's style statement of a shirt knotted up was the result of a mistake. The actor was given a shirt that was too long and stretched down to his knees. Instead of getting a new one, he simply knotted it up at the waist and carried on with the shoot.
4 The mother
Nirupa Roy was not the first choice for her role in Deewar. Waheeda Rehman was first offered the role, but Yash Chopra decided against it since he had already cast her as Amitabh's wife in Kabhi Kabhie. She would go on to play Amitabh's mother in Trishul, also directed by Yash Chopra.
5 The casting
Gulshan Rai, the producer, wanted Rajesh Khanna to play the part of Vijay. Navin Nischol was to be cast as his younger brother, and Vyjayanthimala and Waheeda Rehman were shortlisted for the mother's role. Rajesh Khanna eventually dropped out due to problems with his date. Yash Chopra, having seen Zanjeer, decided to cast Amitabh Bachchan and Salim-Javed seconded the idea.
6 Amitabh's multi-tasking stint
Amitabh Bachchan worked for Sholay and Deewar simultaneously. He shot for Sholay during the day and Deewar during the night. The shoot for Sholay ended halfway through Deewar, but Amitabh continued to multi-task. He then shot for Yash Chopra's Kabhi Kabhie simultaneously while completing Deewar's schedule.
7 Aaj khush to bahut hoge tum....
The famous death scene in Deewar was ad-libbed, with Amitabh Bachchan setting the tempo and the mood for the scene. Neither Yash Chopra nor the writer duo of Salim-Javed added any pointers for Amitabh's performance in the scene.
8 The second fiddle
Salim-Javed had actually written the script with Ravi (Shashi Kapoor's character) as the hero. Amitabh's performance as Vijay was so intense that it left Shashi Kapoor completely in the background.