Jennifer Lynn Connelly (born December 12, 1970) is an American film actress and former child model. Although starring as early as a teenager in films such as Once Upon a Time in America, Labyrinth and Career Opportunities, she gained critical acclaim following her work in the 2000 drama Requiem for a Dream, and the 2001 biopic A Beautiful Mind, for which she won an Academy Award for Best Supporting Actress, as well as the BAFTA and Golden Globe awards.

Connelly was born in the Catskill Mountains of New York, the daughter of Ilene, an antiques dealer, and Gerard Connelly, a clothing manufacturer who worked in the garment industry. Connelly's father was of Irish Catholic and Norwegian descent, and Connelly's mother was Jewish, a descendant of immigrants from Russia and Poland (Connelly's mother was schooled in a yeshiva). Connelly was raised in Brooklyn Heights, near the Brooklyn Bridge, and attended St. Ann's private school, except for four years the family spent living in Woodstock, New York. One of her father's friends was an advertising executive, who suggested that she audition at a modeling agency.

At the age of ten, Connelly's career started in newspaper and magazine ads, then moved to television commercials. These led to movie auditions and her first film role was as "young Deborah Gelly", a supporting role in Sergio Leone's 1984 gangster epic, Once Upon a Time in America, filmed mostly in 1982 when she was eleven. She next starred in Italian horror-director Dario Argento's Phenomena (1985) and in the coming-of-age movie Seven Minutes in Heaven.