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Diane Keaton, who died at age 79 on Oct. 11 in California, had been experiencing a sharp downturn in her health, a source tells PEOPLE exclusively.<\/p>\n<\/div>\n<\/li>\n
“It was so unexpected, especially for someone with such strength and spirit,” the source says.<\/p>\n<\/div>\n<\/li>\n
The Oscar winner had also listed her Los Angeles “dream home” for sale in March.<\/p>\n<\/div>\n<\/li>\n<\/ul>\n
Diane Keaton<\/a>‘s health had taken a sharp turn in recent months.<\/p>\n \u201cShe declined very suddenly, which was heartbreaking for everyone who loved her,\u201d a friend of the Oscar winner \u2014 who died on Oct. 11 at age 79<\/a> in California \u2014\u00a0tells PEOPLE exclusively. \u201cIt was so unexpected, especially for someone with such strength and spirit.”<\/p>\n The source adds, “In her final months, she was surrounded only by her closest family, who chose to keep things very private. Even longtime friends weren\u2019t fully aware of what was happening.\u201d<\/p>\n Keaton had made at least one major lifestyle change in recent months: In March, she listed her beloved “dream home,” surprising many after she said she had planned to remain there permanently.<\/p>\n The longtime home-flipper, who was renowned in interior design circles for her sophisticated taste, had even written a book about the home, called The House that Pinterest Built.<\/em><\/a> After moving there in 2017, she completed an extensive eight-year renovation. But in March, she listed the five-bedroom, seven-bathroom property<\/a> for $29 million.<\/p>\n In her book, she noted that the inspiration for buying the home was the children’s fable The Three Little Pigs.<\/em> When she was young and her mother read her the story, she took the lesson to heart. The third pig’s indestructable home, of course, “was made of bricks,” she wrote. “I knew I was going to live in a brick house when I grew up.”<\/p>\n