 Born in Nigoline, Province of Brescia, Betti in 1957 moved to Rome, where she became a real-life friend of Federico Fellini.Fellini referred to her as "her boss" and as "the little goddess of ideas", and Betti was a collaborator, a casting director, a script supervisor and a second unit director for many of his films until 1980.As a screenwriter, she also often collaborated with Marco Ferreri and Enrico Oldoini.