The video features the pair synchronised teeth brushing, singing karaoke and drinking shots, reported Ace Showbiz.
The pair appeared on Jimmy Kimmel Live: Game Night to promote the new song.
'Hangover' will be released via School Boy Records/Republic Records.
Psy's breakthrough hit 'Gangnam Style' has now amassed over 2 billion views on Youtube.
"2 billion views... They are very honourable and very burdensome numbers. With appreciation, I will come back soon with more joyful contents!!" he said in a statement.
Psy will follow up the release of 'Hangover' with a new single, to be released globally later this summer.