Who in 2013 had a hit titled "Don't You Worry Child"?

Swedish House Mafia featuring John Martin had a hit in 2012–2013 with “Don’t You Worry Child.” The song was released on September 14, 2012, and became a major chart success during the 2013 music year.

Swedish House Mafia was a Swedish electronic music supergroup consisting of Axwell, Steve Angello, and Sebastian Ingrosso. John Martin supplied the song’s prominent vocals, giving the progressive-house track an emotional, anthemic quality that helped it reach audiences beyond the dance-music scene.

The song was the group’s sixth single and appeared on their compilation album Until Now. It became their biggest hit, reaching number one in Australia, Sweden, and the United Kingdom, while placing in the top 10 in many other countries. It also earned a Grammy nomination for Best Dance Recording at the 2013 awards.

The wording can cause a minor date confusion: the question says the group had the hit “in 2013,” but the single itself was released in 2012. The stored answer remains the canonical act-and-feature credit, and 2013 refers to the song’s continuing chart and awards prominence.