YG Entertainment, PSY's agency, says "Gentleman" was released in 119 countries on Friday.
PSY co-composed the electronic dance music and wrote the lyrics for the song, which pokes fun at a self-claimed gentleman who enjoys his time at a dance club.
Tensions in South Korea are high, with residents wary of a possible missile test by the North. But South Korean Internet users were more interested Friday in PSY's new song than North Korea: "Gentleman" was the most searched keyword on top Web portals.
PSY's manager Hwang Kyu-wan says the video for "Gentleman" will be unveiled at his comeback concert in Seoul on Sunday and will then be uploaded onto YouTube.