Juan Fernando Kubero Díaz is an Argentine rock guitarist, best known as the founder and leader of the rock group La Cofradía de la Flor Solar, and for having been a member of Billy Bond and La Pesada del Rock & Roll and Los Abuelos de la Nada. The Argentine edition of Rolling Stone magazine ranked him 13th in its list of the 100 best guitarists in the history of Argentine rock.

Billy Bond and La Pesada del Rock & Roll (also known as La Pesada del Rock and Roll or La Pesada) was an Argentine supergroup that pioneered hard rock, psychedelic rock and heavy metal in Latin America. It was formed in 1970 by producer Jorge Álvarez (co-founder of the Mandioca record label) and singer and producer Billy Bond, who would become the band's leader.