Christie's first major film role was in The Fast Lady, a 1962 romantic comedy. Her breakout role was as Liz, the friend and would-be lover of the eponymous Billy Liar played by Tom Courtenay in the 1963 film directed by John Schlesinger. Schlesinger, who only cast Christie after another actress dropped out of his film, directed her in her breakthrough role, as the amoral model Diana Scott in Darling (1965), a role which the producers originally offered to Shirley MacLaine. Though virtually unknown before Darling, Christie ended the year 1965 by appearing as Lara Antipova in David Lean's adaptation of Boris Pasternak's novel Doctor Zhivago (1965), which was one of the all-time box office hits, and as Daisy Battles in Young Cassidy, the John Ford-Jack Cardiff directed biopic of Irish playwright Sean O'Casey. In 1966, the 25-year-old Christie was nominated for a BAFTA Award for Best Actress in a Leading Role when she played a double role in Francois Truffaut's Fahrenheit 451 and won th