When you hear a hit song on the radio, almost always you think whoever is singing wrote the song. Well...,that's not always the case. There are a lot of songwriters in the music industry that only write songs, mostly for other artist.

Everyone remembers 'Happy' from Pharrell, the foot tapping, hand clapping anthem.

It was originally written for Cee Lo Green who had to pass on it.

That song became a worldwide sensation for Pharrell and it was written for someone else.

This is but one example of songs that artist passed on and turned out to be a smash hit for another artist.

Check out this list of hit songs and the artist who were supposed to sing them.