She has a twin sister,
Daniela Spanic who played Gilda in a fight scene of
Como tú, ninguna (1994). It was too hard to film the characters of Gilda and Raquel in the same scene, using camera tricks, so the producers contracted Daniela, who is a fashion model, to make this scene "fighting" her real life twin Gabriela, who then, played the part of Raquel. Gabriela revealed this in the Argentinian television show
Almorzando con Mirtha Legrand (1968).