Get Karl! Oh Soo Jung (2007)

it's about getting revenge from your Ex, but here, it's the male lead getting back at his runaway bride

They have the same story, the man gets dumped by the beauty queen,after some year the fate reverses . He became successful and she became poor,then they meet so she tries to seduce all over again .

Mini Spoiler ---*

In Get Karl! Oh Soo Jung they were about to marry each other. However, in Cunning Single Lady they were married and got divorced .

very close plot about a geek dumped by his fiancee transformed to a hot successful man and comes back seeking revenge

They both have similar plots: meeting with a past lover/ crush and years later the female leads looks have deteriorated and meets the lead guy again.
Get Karl was a comical drama just like she was pretty.

The premise is quite similar. Get Karl tells the story of a man who wants to get back with his girlfriend so he has a make-over and becomes successful.

A man changes himself to get revenge on the woman who broke his heart.

Mainly because It has the gorgeous Oh Ji Ho, a dimpled, handsome lead just like in Who's the one, and he's hysterical and sweet as Overweight Karl before he transforms himself into a lean, gorgeous Pro-Golfer. And it has the talented Uhm Jung Hwa as his leading lady upending his life once again.

Both main leads are real bitches in the beginning and change throughout the drama. The transformation in the main lead females are spectacular... :)))