Humsaya (1968)

Born to a Chinese father and Indian mother, Chinese Army Officer Lin Tan is in love and gets married to Sin. On their wedding night, Professor Tao Kai Chen summons him, gets him to undergo plastic surgery to look like Prince Shyam Singh, and arranges for weapons for the Chinese army so that they can attack India. Lin meets alcoholic, disgraced Indian Air Force Squadron Leader Shyam, who was found guilty for killing Vijay Khanna. Alienated from his sweetheart, Leena Sen, he had taken to alcohol and had been befriended by Tao. Lin is then instructed to impersonate Shyam, kill him, and take his place--but Shyam overpowers him, and instead Tao mistakenly kills Lin. Shyam dons Lin's guise and returns home to Delhi--where he hopes to clear his name. This is where he will face many challenges when Leena will even refuse to speak with him, the community in general will shun him, and the arrival of Sin, along with a peace delegation, will complicate matters even more--as she thinks that he is her husband and wants to consummate her marriage.