In November 2012, Shakira revealed in an interview with Billboard magazine that she had begun writing new material and working with various producers for a new record.
"23" was recorded at Estopa Estudios in Sant Feliu de Llobregat, Barcelona by Dave Clauss and Eric Eylands served as engineering assistant.
[1] "I put a pair of headphones on him and he was listening really intently and after I finished the last little bit of the song ... he goes 'muau' and he just stayed there on the final recording, just like it happened.
[3] In the song, she reflects on the moment she first met Piqué, expressing that she felt an immediate connection between them and that fate played a role in bringing them together when he was just 23.
[14] At Sputnikmusic, Brendan Schroer review the instrumentation of the song like an "Shakira's highly honest and reflective performances".
[15] Elysa Gardner of USA Today defines the song as "a gently blissed-out track" and praised the fact that Shakira credited her son Milan as the "youngest background vocalist in the world!".
[16] At The New York Times' Jon Pareles said that "23" shows "her professions of love sound both innocent and obsessive, and the idiosyncrasies of her English lyrics".