"Somebody That I Used to Know" is a song written, produced and performed by Australian musician and singer Gotye, featuring vocals from New Zealand singer Kimbra. The song samples Luiz Bonfá's 1967 instrumental song "Seville", with additional instrumentations of beats and a xylophone playing a melody based on "Baa, Baa, Black Sheep". The song was released in Australia and New Zealand through Eleven Music on 5 July 2011 as the second single from Gotye's third studio album, Making Mirrors (2011). It was later released by Universal Music in December 2011 in the United Kingdom, and 20 January 2012 in Ireland and the United States. "Somebody That I Used to Know" was written and recorded by Gotye at his parents' house on the Mornington Peninsula in Victoria, Australia, and is lyrically related to the experiences he has had with romantic relationships.

Wouter André "Wally" De Backer, known professionally as Gotye, is an Australian singer-songwriter and multi-instrumentalist. His 2011 single "Somebody That I Used to Know", reached number one on the Billboard Hot 100 and became the best-selling song of 2012. This made him the fifth Australian-based artist to top the chart and the second born in Belgium.