Diane Keaton’s friends say they feared the beloved Oscar-winning actress was battling a secret illness in the weeks before her death – after noticing her dramatic weight loss and growing frailty.

As RadarOnline.com reported, the 79-year-old star of Annie Hall and The Godfather died in California on October 11.

A Private Struggle Hidden Behind Her Famous Smile

Source: MEGAFriends said Keaton may have died from recurring skin cancer.

Sources close to the actress now tell us Keaton’s death may have been caused by complications linked to a recurrence of skin cancer, the same disease she had battled twice before.

Those close to her said the decline was “sudden and shocking,” with some friends admitting they had begun to worry her cancer had returned when her weight dropped dramatically over the summer.

“Everyone noticed she’d lost a lot of weight very quickly,” a longtime friend claimed. “She looked fragile, which was unusual for someone with so much spirit. We were all scared it might be her cancer again, but she didn’t want anyone fussing over her.”

The friend added Keaton kept “everything” private and was determined to face her illness on her own terms.

Songwriter Carole Bayer Sager, who visited Keaton a few weeks before her death, said she was “stunned” by the actress’ physical change in her final days.

She said: “I saw her two or three weeks ago, and she was very thin. She had lost so much weight.”

The two women, who collaborated on Keaton’s single First Christmas in 2024, had been close for decades.

Health Decline After Wildfire Displacement

Source: MEGASinger Carole Bayer Sager was stunned by Keaton’s frail appearance.

Sager added Keaton remained upbeat during their final meeting.

“She was a magic light for everyone,” she said. “I just loved her. She was so special, she just lit up a room with her energy. She was happy and upbeat and taking photographs of everything she saw. She was completely creative; she never stopped creating.”

Friends said Keaton’s health appeared to decline after she relocated temporarily to Palm Springs earlier this year when her Brentwood home was damaged during California’s wildfires.

“She had to go to Palm Springs because her house had been damaged inside, and they had to clean everything,” Sager said. “When she came back, I was kind of stunned by how much weight she’d lost.”

A film industry source close to Keaton said her final months were “quiet but content.”

The friend said: “She was funny right up until the end. She lived exactly how she wanted to – on her own terms, surrounded by the people and things she really loved. In these last few years, she kept a close circle, and she liked it that way.”