"X" is a song by American singer Nicky Jam and Colombian singer J Balvin. Written by the two singers, Juan Diego Medina, Giordano Ashruf and its producers, Jeon and Afro Bros, it was released by Sony Music Latin on March 2, 2018. It is a Spanish dancehall song, featuring a synth trumpet hook and elements of reggae, reggaeton, Latin pop and Afrobeats. A Spanglish version of the song was released on April 27, 2018. On June 28, 2018, a remix version featuring vocals by artists Maluma and Ozuna was released. The accompanying audio was also released on Nicky Jam's YouTube channel on the same day. The song topped the charts in Spain, Italy, Portugal, Bolivia, El Salvador, Panama, Paraguay and Peru. Nicky Jam performed the song solo during the 2018 FIFA World Cup closing ceremony.

Nick Rivera Caminero, known by his stage name Nicky Jam, is an American singer. He is best known for hits such as "X", "Travesuras", "En la Cama", "Te Busco", "El Perdón", "Hasta el Amanecer", and "El Amante"; the later three are from his 2017 album Fénix. He has frequently collaborated with other Latin artists such as Daddy Yankee, J Balvin, Ozuna, Plan B and Anuel AA. While his early music exemplified traditional fast-paced reggaeton, his newer compositions place more emphasis on sung vocals and romantic lyrics.