Mastroianni was born to French actress Catherine Deneuve and Italian actor Marcello Mastroianni. Her parents were both married to other people at the time of their affair and stayed together for four years, eventually separating in 1975 when Mastroianni was two years old. She later revealed that she could not recall them being together saying "I've never seen my parents together, never in my whole life. They split when I was two, so I've no recollection of them as a couple. I've never even seen them kiss – except in the movies. "