Keaton was best known for her roles in Annie Hall, Reds and The Godfather films.

American actress Diane Keaton, known for her Oscar-winning performance in 1977’s Annie Hall and her role in The Godfather films, has died at the age of 79.

Keaton died in California and her loved ones have asked for privacy, a family spokesperson told People magazine on Saturday.

Keaton, who appeared in more than 60 films, stood out in Hollywood with a personal style that favoured androgynous looks: suits, turtleneck sweaters and her trademark hats.

The actress shot to fame in the 1970s with her role as Kay Adams, the girlfriend and eventual wife of Al Pacino’s Michael Corleone in The Godfather trilogy as well as her collaborations with director Woody Allen.

Keaton frequently worked with Allen, portraying the titular character in Annie Hall, the charming girlfriend of Allen’s comic Alvy Singer.

“It was an idealised version of me, let’s put it that way,” Keaton said about the film in an interview with the United States TV network CBS News in 2004.

The film also garnered Oscars for best picture, best director and best original screenplay, cementing Keaton’s place as one of the industry’s top actresses and an offbeat style icon as well.

She made a total of eight films with Allen, including 1979’s Manhattan.

Her star-making performances in the 1970s were not a flash in the pan as she would continue to charm new generations for decades, thanks in part to a longstanding collaboration with filmmaker Nancy Meyers, with whom she made four films.

A BAFTA and Golden Globe winner, Keaton scored Oscar nominations three other times for best actress for Reds, Marvin’s Room and Something’s Gotta Give.

Her many beloved films included The First Wives Club, Father of the Bride, The Family Stone and the Book Club movies.

Born Diane Hall in Los Angeles on January 5, 1946, Keaton was romantically involved with Allen, Pacino and Warren Beatty (her Reds costar), but she never married.

“I think I was really afraid of men and also very attracted to extremely talented people that were dazzling,” she told Elle magazine in 2015. “I don’t think that makes for a good marriage with a person like me, someone who just didn’t adjust well.”

Keaton is survived by her two children, Dexter and Duke, whom she adopted in her 50s.