Born as María del Pilar Gaos Meizoso in La Coruña, Spain, in 1949, she made her debut in Mexico in 1962. Her presence was like a fresh drop in the world of modern singers and young Rock & Roll performers. She was the younger sister of Mayté Gaos, another "rock and roller."

Pily was beautiful, charming, cheerful, petite, and had a childlike appearance. She sang like a girl in the process of growing up. Her most notable hits included "Las trencitas," "Mi novio esquimal," and "Aburrida y sola."

She retired from the music world and passed away from cancer on April 10, 2009, in Spain. She also appeared in Mexican cinema, starring in Demonios sobre ruedas (1967), La batalla de los pasteles (1966), and Un ángel de mal genio (1964).