Hey guys i'm looking for a drama where the main couple is an idol and a normal person.

Some dramas like this include 

the producers

second couple in masters sun

Cinderalla and the four knights (kinda)

You who came from the stars (kinda)

@Panda I don't think she means a real idol + actor, I think she means the characters of the drama 

Star of the Universe
IF I didn't remember wrongly, Because of You
Bad Girls
Code Name : Jackal
http://mydramalist.com/3097-glowing-she

Just an average drama but enjoyable enough for what you're looking for.
Full House
Smiling Pasta
Shut up Flower boy band
Monstar
That Fool
ToGetHer
Over the Rainbow
Heartstrings (he's not a full-fledged idol but he is a super popular musician within his campus)
Ho Goo's Love (female lead is a swimming star)
Fantastic (male lead is a famous actor and in my opinion this is a very good, underrated drama)
Uncontrollably Fond