Railway Station in the film is named Bhavani Junction.Four years later a film was made in 1985 with the title Bhavani Junction.Staring Shashi Kapoor,Shatrughan Sinha,Zeenat Aman,Rati Agnihotri,Prem Chopra,Mazhar Khan and Mahesh Anand.
Sanjeev Kumar signed the film because it was made by his friend and former class mate Virendra Kumar. They both were from Fimalaya school of acting. But Sanjeev suffered a heart attack and was advised bed rest. This is when Virendra decided to replace Sanjeev Kumar with a young newcomer, Raj Babbar. This decision did not sit well with the lead actress Sulakshna Pandit. She had signed the film because it starred her boyfriend Sanjeev Kumar. Sulakshana wanted to opt out of the film but was advised by Harmesh Malhotra to not let go of a good role. Raj Babbar went to visit Sanjeev to seek his permission and blessings to replace him in the film. Sanjeev told Raj Babbar the role was a very good one and if the film clicked at the box office, he would become a big hero.
In the late 50's, Guru Dutt had launched a film titled,"Raaz". The film starred Sunil Dutt, Waheeda Rehman, Rehman, Directed by Shashi Bhushan. After 10 days, Guru Dutt decided to shelved the film. Then in the early 60's, he relaunched another film titled "Raaz" with himself, Waheeda Rehman and Rehman. After shooting 12 reels for unknown reasons,he shelved the film. The movie was based on the novel "The Woman In White". Raj Khosla who was a assistant on Raaz, decided to use the same script and made "Woh Kaun Thi".
Remake of Do Bhai.
Raj Babbar's dates were a major problem. His secretary gave all of his dates to Harmesh Malhotra's Poonam. This cause producer Veerendra Singh alot of grief. Raj Babbar felt terrible about this because Veerendra Singh gave Raj Babbar a place to stay when he arrived in Bombay.