Diane Keaton (born January 5, 1946) is an American film actress, director and producer. Keaton began her career on stage, and made her screen debut in 1970. Her first major film role was as Kay Adams-Corleone in The Godfather (1972), but the films that shaped her early career were those with director and co-star Woody Allen beginning with Play It Again, Sam in 1972. Her next two films with Allen, Sleeper (1973) and Love and Death (1975), established her as a comic actress. Her fourth, Annie Hall (1977), won her the Academy Award for Best Actress.

Keaton subsequently expanded her range to avoid becoming typecast as her Annie Hall persona. She became an accomplished dramatic actress, starting in Looking for Mr. Goodbar (1977) and received Academy Award nominations for Reds (1981) and Marvin's Room (1996). Some of her popular later films include Father of the Bride (1991), The First Wives Club (1996), and Something's Gotta Give (2003). Films Keaton has been in have earned a cumulative gross of over USD$1.1 billion in North America. In addition to acting, she is also a photographer, real estate developer, and occasional singer.

Born Diane Hall in Los Angeles, California, she is the oldest of four children. Keaton has one brother, Randy Hall (b. March 21, 1948) and sisters Robin Hall (b. March 27, 1951) and Dorrie Hall (b. April 1, 1953). Her mother, Dorothy (née Keaton; 1921-2008), was a homemaker and amateur photographer, and her father, Jack Hall (1921–1990), was a real estate broker and civil engineer. Her father came from an Irish American Catholic background, and her mother came from a Methodist family. Keaton was raised a Methodist by her mother. Her first ambition to become an actor came after seeing her mother win the "Mrs. Los Angeles" pageant for homemakers. Keaton claimed that the theatricality of the event inspired her to become a stage actor. She has also credited Katharine Hepburn, whom she admires for playing strong and independent women, as one of her inspirations.