Chocolat (2002)

Blurb:
How far would you go to meet your favorite boy band? Kum-Ji was little late getting under the spell of the chart topping boy band DDL. Unable to join the DDL fan club, she almost gives up meeting her idols until she develops a cunning plan, becoming a top member of their rival fan club for a brand-new boy group, Yo-I (Chocolat). This way she can always be near Yo-I at all their concerts. Funnily enough Yo-I always seem to play the same shows with DDL. It’s almost the perfect plan except it’s really complicated being a super fan for one band when your heart lies with another. Follow the adventures of Kum-Ji in this full-blown romantic comedy as she tries to keep her scheme together.

Source: www.anisearch.com/manga/2721