Major Characters:

Seo Joohyun - Seohyun (25)

Wedding dress' designer

broken hearted girl
 

Kevin Woo (26)

Singer and Music Composer

Seohyun's current boyfriend
 

Kim Myungsoo  (25)

TOP Actor

Seohyun's first love
 

Lee Sungyeol (26)

model

Seohyun's eternal love
 

Nam Woohyun (26)

Seohyun's personal assistant

The Clique :

Key Kim Kibum  (25) 

Seohyun's BFF

Nicole's fiancé

Nicole Jung (25)

Seohyun's BFF

Key's fiancé

Choi Sooyoung (25)

Seohyun's BFF

Hyungshik's wife

Park Hyungshik (26)

Seohyun's BFF

Sooyoung's husband

Family :

Seo Jaejoong (55) 

Former member of DBSK & World top Music Composer

Seohyun's father

Tiffany Hwang (51)

World Fashion designer

Seohyun's mother
 

Seo Sungjong (21)

part-time designer and model

Seohyun's little brother

and some minor characters would be added while the story goes on...