Taken from D-Addicts:
The drama tells the story of Kim Joo Won (Hyun Bin), an arrogant and eccentric CEO who maintains the image of seeming perfection, and Gil Ra Im (Ha Ji Won), a poor and humble stuntwoman whose beauty and body are the object of envy amongst top actresses. Their accidental meeting, when Joo Won mistakes Ra Im for actress Park Chae Rin, marks the beginning of a tense, bickering relationship, through which Joo Won tries to hide a growing attraction to Ra Im that both confuses and disturbs him. To complicate matters further, a strange sequence of events results in them swapping bodies.So, if you read the synopsis, you will find out that it's very interesting and the plot is rarely to be found in most Korean drama. It's airing on Saturday and Sunday (Korean time), so the English subs are usually released few days after it has been airing (most likely in Tuesday-Thursday).
If you look at the episode ratings, you will see why i am so eager to watch this drama