"It Ain't Me" is a song by Norwegian DJ Kygo and American singer Selena Gomez. It was released by Interscope Records, Sony and Ultra on 16 February 2017 as the lead single from Kygo's first EP, Stargazing. The song was written by Kygo, Andrew Watt, Brian Lee, Ali Tamposi and Gomez. It was produced by Kygo, Watt, Ben Rice and Louis Bell. A dance-pop, electropop and tropical house song, "It Ain't Me" comprises an acoustic guitar line, and a build-drop arrangement in its chorus featuring pulsing piano notes, bass, synthesizers, finger-snap claps and pan flute melodies. Gomez sings the track in a husky tone, while in the chorus her vocals are reduced to recurring syllables. The lyrics are nostalgic and narrate a past relationship ruined by alcoholism.