La luna (1979)

Recently widowed American opera diva Caterina takes her teenaged son Joe with her on a long singing tour to Italy. Absorbed in her hectic work in various Verdi operas around Rome, Caterina is soon shocked to discover that her troubled and lonely son has become a heroin addict. Her desperate attempts to wean the youth off the drug result in an incestuous relationship, but also in a possibility to reunite Joe--maybe even herself--with his real father, whose existence she has kept a secret from him.