Gustavo Roy Díaz (born in Santurce, Puerto Rico), known publicly as Big Boy, is a hip hop/reggaeton artist.

Díaz, a pioneer of reggaeton music, began his music career at the age of eighteen when he signed with Musical Productions to release his first album Mr. Big in 1993. The album sold more than 100,000 copies.

By the age of twenty-two, artist Big Boy achieved recognition in other Latin American countries such as Mexico, Bolivia, and Costa Rica. 1999's Big Impact saw an experimentation with other genres of music such as rap, techno, and reggae.

Continuing with the immersion of other genres, Díaz's 2005 release El Comeback sees the artist flirting with the musical rhytms of merengue, bachata, and mariachi.