Born in Getxo, Spain, Velázquez played the cello as his main instrument, attending conservatories in Bilbao and Vitoria before studying composition in Paris and Madrid. He first worked with filmmaker Bayona early in both of their careers, on the 2002 short film El Hombre Esponja. They would reunite several more times, including for 2007's The Orphanage and 2012's The Impossible. Velázquez also found work on Spanish television series such as the 2007's Gominolas and 2013's Cuéntame un Cuento, while projects with other film directors included 2006's The Backwoods, the 2007 Julianne Moore vehicle Savage Grace, 2010's Devil, and Brett Ratnor's Hercules from 2014.