In 2005, Sanz collaborated with Shakira on her song "La Tortura". Co-written by Sanz, the song became an international hit, breaking the record for the most weeks at the number one spot on the Hot Latin Songs chart. The song exposed Sanz to a more diverse audience, and helped build anticipation for his next release. The first single from the album El Tren de los Momentos, "A la Primera Persona", became his first song to enter the Billboard Hot 100, peaking at number 100 on the chart. The record was also noted for its guest appearances, which featured Shakira, Juanes, Alex González of Maná, and Residente of Calle 13.
In the spring of 2007, Sanz suffered a mental breakdown and took two months off in the middle of a world tour at the request of his doctor. The breakdown was caused by several events in his personal life, including the death of his father in 2005, his separation with Mexican model and actress Jaydy Mitchel, and his announcement that he had a three-year-old son outside of his marriage with Mitchel. He commented on the situation, saying "You have to put things in perspective. It was stress, something that had never affected me, but this time, yes, it did. So I had to pay. A doctor told me to stop for a couple of months to recuperate completely." Sanz spent time in therapy, a time which "helped [him] a lot" and gave him "more power" to perform.