The producers considered Danny Denzongpa for the role of bandit chief Gabbar Singh , but he could not accept it as he was committed to act in Feroz Khan 's Dharmatma ( 1975 ) , under production at the same time . Amjad Khan , who was the second choice , prepared himself for the part by reading the book Abhishapta Chambal , which told of the exploits of Chambal dacoits . The book was written by Taroon Kumar Bhaduri , the father of fellow cast member Jaya Bhaduri . As cast members had read the script ahead of time , many was interested in playing different parts . Pran was considered for the role of Thakur Baldev Singh , but Sippy thought Sanjeev Kumar was a better choice . Initially , Dharmendra was also interested to play the role of Thakur . He eventually gave up the role when Sippy informed him that Sanjeev Kumar would play Veeru if that happened , and would be paired with Hema Malini , who Dharmendra was trying to woo . Dharmendra knew that Kumar was also interested in Malini . Sippy wanted Shatrughan Sinha to play the part of Jai , but there was already several big stars signed , and Amitabh Bachchan , who was not extremely popular yet , lobbied hard to get the part for himself .