Los Hermanos Castro was a Mexican close-harmony singing group. The Castro Brothers were famous for their four-part harmony with Gualberto’s countertenor / tenor voice often singing lead. Later, their first cousin, Benito Castro entered the group as a musician and a singer, but he gradually turned into a comedian like his late father, Arturo "Bigotón" Castro. They recorded numerous albums; one of their most famous hits, "Yo sin ti", written and arranged by Arturo Castro, became a popular song throughout Mexico and South America.