Diane Keaton's cause of death: What happened to the Oscar-winning actress?

Diane Keaton died aged 79, on October 11, 2025, in Los Angeles, California. Her family later confirmed that the cause of death was pneumonia. The legendary, Oscar-winning actress's career spanned over five decades, establishing her as one of the Hollywood's most beloved and versatile performers.

Keaton rose to prominence in the New Hollywood movement, most famously for her collaborations with Woody Allen, including her Academy Award-winning role as the title character in Annie Hall (1977). She also cemented her legacy with her iconic portrayal of Kay Adams-Corleone in The Godfather trilogy. In her later career, Keaton featured in romantic comedies and dramas.

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Diane Keaton dies at 79: Family confirms pneumonia as cause of death

Diane Keaton at the TCL Chinese Theatre (Image via Getty)

In an interview with People magazine, Diane Keaton's family confirmed the actress's cause of death. Four days after her death, the family released the following statement on October 15, 2025:

"The Keaton family are very grateful for the extraordinary messages of love and support they have received these past few days on behalf of their beloved Diane, who passed away from pneumonia on October 11."

Diane Keaton was born Diane Hall on January 5, 1946, in Los Angeles, California, as the eldest of the four children of her father, a civil engineer, and her mother, a homemaker and amateur photographer, who inspired Keaton's creative side. She attended Santa Ana High School, graduating in 1964, where she developed an interest in acting and singing.

Keaton briefly attended Santa Ana College before dropping out after a year to move to Manhattan, New York, to pursue an acting career. To join Actors' Equity Association, she adopted her mother's maiden name, Keaton, as there was already a Diane Hall in the union. She studied at the Neighborhood Playhouse School of the Theatre under the renowned Sanford Meisner.

She began her career on stage, most famously as an understudy in the first Broadway run of Hair. Her first breakthrough came in 1968, when she was cast in Woody Allen's Broadway production of Play It Again, Sam, which earned her a Tony Award nomination. In 1972, she further gained fame appearing in The Godfather, playing Kay Adams, following which she was established as an iconic face in the industry.

Keaton never married, but she adopted two children during her 50s: a boy and a girl. Her daughter, Dexter, was born in December 1995 and adopted in 1996. And her son, Duke, was born in February 2000 and adopted in 2001. A source confirmed to People that only the closest of Keaton's family knew about her declining health and that she was around them during her final moments. They stated:

"In her final months, she was surrounded only by her closest family, who chose to keep things very private. Even longtime friends weren’t fully aware of what was happening."

During her final months, Diane Keaton's declining health led to significant lifestyle changes. She stopped her routine of daily dog walks in her neighborhood, and in March 2025, she listed her Los Angeles "dream home" for sale. Speaking to People, a source confirmed:

"She lived in Brentwood for many years. She loved her neighborhood. Up until just a few months ago, she'd walk her dog every day. She was usually dressed the same, with a hat and her signature sunglasses regardless of the weather."

Diane Keaton's former frequent co-stars, such as Steve Martin and Kimberly Williams-Paisley, Bette Midler and Goldie Hawn, and Jane Fonda, paid tribute to her. Other stars who offered condolences include Leonardo DiCaprio, Robert De Niro, Meryl Streep, and Ben Stiller.

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