Roop Tera Mastana(1972)

Ajit, the Personal assistant to Princess Usha, does away with her and brings along a look-alike, Kiran, to pose as her for a few days. Kiran, although poor, refuses to do so, and Ajit threatens her and her family, and she reluctantly agrees. She meets with Usha's fiance, a Prince himself, and falls in love with him, not realizing that her feelings will soon be history when those few days come to an end, and she must then give up her wealthy lifestyle and go back to being poor again.