Cinderella Man

Dae-san sells his own clothing designs at a small shop in Dongdaemun Market and all he thinks about is getting rich. One day, he crosses path with Joon-hee and finds that they share an uncanny resemblance to each other. Joon-hee, who is also the heir of a fashion empire, asks Dae-san if he could pose as him for a month. While secretly posing as Joon-hee, Dae-san uses his savvy business skills to outmaneuver Lee Jae-min and also finds true love. But then his cover is blown... Source: AsianWiki