Psy and Heize collaborated for the song on Psy's upcoming 9th full-length album. 

On April 18th, P NATION unveiled another track set to appear on Psy's upcoming 9th full-length album 'PSY 9th.' The song, titled "Sleepless" is the 5th track on the album and features singer Heize. 

"Sleepless" is a remake of the song by Crying Nut, originally released in 2001. Many are looking forward to Psy and Heize's rendition of the classic song. 

Meanwhile, 'Psy 9th' is set for release on April 29 at 6 PM KST.