Watch Anokhi Pehchan
"Anokhi Pehchan" (1972) is a Bollywood movie about an army officer who meets a little boy who takes him for his father. When he meets the child's mother, she shows him a picture of her husband, who he strongly resembles. The husband is also an army officer and he is missing. The protagonist promises to try and find him. He also gets very close to the family, and people assume he is married to the woman with the child.