Each December YouTube wraps things up with a self-produced compilation reel highlighting the biggest viral hits of the year.

With a catchy remix of some of 2013's biggest hit songs stringing together parody scenes and clips from the year's most unique and popular videos, 'YouTube Rewind: What Does 2013 Say?' is a grab bag of toe-tapping fun.

It is not surprising that a couple South Korean stars made their way into the mix, K-Pop is, after all, well on its way to becoming one of the world's most popular music genres.

Psy's "Gentleman," the follow up single to 2012's epically popular "Gangnam Style," proved to be another smash hit for the quirky Korean rapper. The song prominently featured in the YouTube Rewind video along with other big hits of the year like Robin Thicke's "Blurred Lines," "Can't Hold Us" by Macklemore and Ryan Lewis, and the Harlem Shake, among others.

DJ Earworm did the remixing for the clever 2013 mashup vid which, aside from featuring the biggest songs of the year, refers to other viral favorites like Convos With My 2-Year-Old, Epic Rap Battles of History, and Jenna Marbles.

Iconic K-Pop girl group Girls' Generation also makes a brief appearance, featured due to the tremendous success of their "I Got a Boy" single. Since the song's release on January 1, the music video has accumulated nearly 80 million views, a number that continues to increase daily.

Within 12 hours of its release on December 11, YouTube's year-end compilation has already been viewed over four million times.

Check out the 'YouTube Rewind: What Does 2013 Say?' video below