Park Jae-sang (born December 31, 1977), hangul: 박재상, hanja: 朴載相, better known by his stage name Psy (Korean: 싸이, IPA: [s͈ai]; /ˈsaɪ/ SY), stylized PSY, is a South Korean singer, songwriter, rapper, dancer, record producer and television personality. Psy is known domestically for his humorous videos and stage performances, and internationally for his hit single "Gangnam Style". The song's refrain "Oppan Gangnam Style" (translated as "Big brother (to a female) is Gangnam style", with Psy referring to himself) was entered into The Yale Book of Quotations as one of the most famous quotations of 2012.

On October 23, 2012, Psy met UN Secretary General Ban Ki-moon at the United Nations Headquarters where Ban expressed his desire to work with the singer because of his "unlimited global reach". On December 21, 2012, his music video for "Gangnam Style" exceeded one billion views on YouTube, becoming the first video to do so in the website's history. Psy was subsequently recognized by the media as the "King of YouTube". On May 31, 2014, the video for PSY's Gangnam Style hit two billion views.