Grammy snub aside, the staggering success of "Gangnam Style" became the story that nobody expected -- one billion Youtube hits, instant worldwide fame and, perhaps the most important outcome of all, K-pop's long overdue recognition in the States.

K-pop's seemingly overnight introduction to the American music scene is actually far from accurate. While Psy is the first Korean artist to achieve a mainstream hit in the U.S., the rapper is not the first to be associated with an American musician. For example, his labelmates, Big Bang, are buddies with Ludacris and Flo Rida, while K-pop R&B singer Se7en goes way back with Fabolous, Lil Kim and Amerie.

To show just how deep Korea's ties to U.S. artists run, we charted Korean-American collabos that slipped under everyone's radar these past few years.

Did any connections surprise you? Anything we missed? Let us know!