Cameron is the daughter of Emilio Díaz, a Cuban-American, and his Anglo-German and Native American wife. She has a sister called Chimene Diaz. Cameron left home at sixteen and was discovered by a photographer at a party who got her a place with the Elite Modelling Agency. Cameron worked as a model in Japan, Australia, Mexico, France and Morocco, attending High School at Long Beach Poly, California, where she was a half-time dancer at football games and graduated in the class of 1990. In 1993, still modelling, she auditioned for a bit part in The Mask
and (to her surprise) was cast as its leading lady. She then took roles in low budget movies, but quickly rose to dizzy heights. Cameron lived with producer Carlos de la Torre for five years. In November 2000, she was engaged to the actor Jared Leto
, but they broke up the following year. In 2007, she and Justin Timberlake
split after three years together.