K-Pop has officially arrived in America, thanks to the recent popularity of groups like Girls' Generation and 2NE1.

Korean pop music has been spreading so far and wide that in 2011, Billboard launched its very own Korea K-Pop Hot 100 chart.

With YouTube numbers reaching Justin Bieber and Lady Gaga levels, K-Pop groups are beginning to pick up traction in America.

But the phenomenon is nothing new outside of the US. In the last decade or so, K-Pop has dominated music charts in Japan, Southeast Asia, the Middle East, Latin America and beyond.

In May 2011, thousands of K-Pop fans held a nasty protest outside the Louvre in Paris, after a show (dubbed Europe's first K-Pop concert) had sold out.

Major news organizations have also jumped on the K-Pop train. Just last week, Al Jazeera's 101 East presented a 25-minute documentary titled, South Korea's Pop Wave.

On Tuesday, David Letterman welcomed all nine members of Girls' Generation on The Late Show (see video below). Making their US TV debut, the group performed their hit single The Boys, which debuted at number one in Korea back in October. The Korean version of the song also debuted on top of the Billboard K-Pop Hot 100.

The girl group returned to US TV stations the very next day, with an appearance on Live! with Kelly.

In 2012, expect more US headlines about K-Pop acts like Girls' Generation, Wonder Girls and the all-male group BEAST, who will embark on a 21-city world tour this month.

Click through for a list of K-Pop super stars expected to make a lot of noise in America this year.

What other K-Pop acts are you excited about this year? Share your thoughts below.