Diane Keaton, the Oscar-winning star of ‘Annie Hall,’ ‘The Godfather’ films and ‘Father of the Bride,’ whose quirky, vibrant manner and depth made her one of the most singular actors of a generation, has died. She was 79.

Details of Keaton’s death, including the cause, were not immediately available.

The unexpected news was met with shock around the world. Keaton was the kind of actor who helped make films iconic and timeless, from her “La-dee-da, la-dee-da” phrasing as Annie Hall, bedecked in that necktie, bowler hat, vest and khakis, to her heartbreaking turn as Kay Adams, the woman unfortunate enough to join the Corleone family.

Among her many memorable roles, she starred as a career-driven woman who unexpectedly becomes a caregiver in ‘Baby Boom,’ the loving mother in the cherished ‘Father of the Bride’ remake, and an empowered woman finding her way in ‘First Wives Club.’ In ‘Something’s Gotta Give,’ Keaton portrayed a divorced playwright entangled with Jack Nicholson’s character, further solidifying her status as a beloved cinematic figure.

She played a businessperson who unexpectedly inherits an infant in “Baby Boom,” the mother of the bride in the beloved remake of “Father of the Bride,” a newly single woman in “First Wives Club,” and a divorced playwright who gets involved with Jack Nicholson’s music executive in “Something’s Gotta Give.”

Keaton won her first Oscar for “Annie Hall” and would go on to be nominated three more times, for “Reds,” “Marvin’s Room” and “Something’s Gotta Give.”

In her very Keaton way, upon accepting her Oscar in 1978 she laughed and said, “This is something.”

Keaton was born Diane Hall in January 1946 in Los Angeles, though her family was not part of the film industry she would find herself in. Her mother was a homemaker and photographer, and her father was in real estate and civil engineering.

Keaton was drawn to theater and singing while in school in Santa Ana, Calif., and she dropped out of college after a year to make a go of it in Manhattan. Actors’ Equity already had a Diane Hall in their ranks, and she took Keaton, her mother’s maiden name, as her own.

She studied under Sanford Meisner in New York and has credited him with giving her the freedom to “chart the complex terrain of human behavior within the safety of his guidance. It made playing with fire fun.”

“More than anything, Sanford Meisner helped me learn to appreciate the darker side of behavior,” she wrote in her 2012 memoir, “Then Again.” “I always had a knack for sensing it but not yet the courage to delve into such dangerous, illuminating territory.”

She started on the stage as an understudy in the Broadway production for “Hair,” and in Allen’ s “Play It Again, Sam” in 1968, for which she would receive a Tony nomination.

Keaton made her film debut in the 1970 romantic comedy “Lovers and Other Strangers,” but her big breakthrough would come a few years later when she was cast in Francis Ford Coppola’s “The Godfather,” which won best picture and become one of the most beloved films of all time. And yet even she hesitated to return for the sequel, though after reading the script she decided otherwise.

The 1970s were an incredibly fruitful time for Keaton thanks in part to her ongoing collaboration with Allen in both comedic and dramatic roles. She appeared in “Sleeper,” “Love and Death,” “Interiors,” Manhattan,” “Manhattan Murder Mystery” and the film version of “Play it Again, Sam.”

Allen and the late Marshall Brickman gave Keaton one of her most iconic roles in “Annie Hall,” the infectious woman from Chippewa Falls whom Allen’s Alvy Singer cannot get over. The film is considered one of the great romantic comedies of all time, with Keaton’s eccentric, self-deprecating Annie at its heart.

In the New York Times, critic Vincent Canby wrote, “As Annie Hall, Miss Keaton emerges as Woody Allen’s Liv Ullman. His camera finds beauty and emotional resources that somehow escape the notice of other directors. Her Annie Hall is a marvelous nut.”

Keaton and Allen were also in a romantic relationship, from about 1968, when she met him while auditioning for his play, until about 1974. Afterward they remained collaborators and friends.

“He was so hip, with his thick glasses and cool suits,” Keaton wrote in her memoir. “But it was his manner that got me, his way of gesturing, his hands, his coughing and looking down in a self-deprecating way while he told jokes.”

She was also romantically linked to Al Pacino, who played her husband in “The Godfather,” and Warren Beatty who directed her and whom she co-starred with in “Reds.” She never married but did adopt two children when she was in her 50s: a daughter, Dexter, and a son, Duke.

“I figured the only way to realize my number-one dream of becoming an actual Broadway musical comedy star was to remain an adoring daughter. Loving a man, a man, and becoming a wife, would have to be put aside,” she wrote in the memoir.

“The names changed, from Dave to Woody, then Warren, and finally Al. Could I have made a lasting commitment to them? Hard to say. Subconsciously I must have known it could never work, and because of this they’d never get in the way of achieving my dreams.”

The Associated Press contributed to this report.