But what do the lyrics of the song mean, and what's the story behind Psy's trademark dance move?
If you're just hearing about the Gangnam craze for the first time, here's a quick cheat sheet to get you up to speed.
LUCY NICHOLSON/REUTERS Host Kevin Hart (L) does Psy’s signature “horse-riding dance” with the South Korean rapper during the 2012 MTV Video Music Awards.
WHAT DOES 'GANGNAM STYLE' MEAN?
Gangnam is a wealthy neighborhood in the South Korean city of Seoul where young people go to party. In the song, Psy describes the kind of guy he is and the kind of girl he wants, painting caricatures of the ostentatious culture of people who hang out in Gangnam.
As The Atlantic pointed out in an in-depth article last month, behind the flashy costumes and killer dance moves in Psy's video, there's a subtle commentary on class in South Korea.
WHAT DOES THE CHORUS, 'OPPAN GANGNAM STYLE,' MEAN?
It roughly means something like 'Your man has Gangnam Style.' 'Oppa,' which literally means 'older brother,' is an affectionate term girls use to address older guy friends or a boyfriend. It can also be used as a first-person pronoun, as PSY does here — in this case, he's telling a woman that he has Gangnam style.
Kevin Mazur/WireImage Getting on that high horse. Korean rapper Psy shows his signature move, which he calls the “horse-riding dance.”
WHAT'S THE DEAL WITH HIS SIGNATURE DANCE?
"It's a horse-riding dance," PSY explained in an interview with NY1 anchor Michelle Park. "So there is an invisible horse, and you're on it." (In the video, Psy first does the dance in the middle of a posh-looking stable.)
The singer manages to turn an activity typically associated with the wealthy into a hilarious, arm-flapping dance move.
HOW DO YOU SAY 'PSY?'
It's pronounced like 'sigh,' short for 'psycho.'
WHAT'S NEXT FOR PSY?
He signed with Schoolboy Records, the label of Justin Bieber's manager Scooter Brown, so we may soon be seeing more of him stateside.
http://youtu.be/60MQ3AG1c8o