Diane Keaton's final moments have been revealed in a 911 call as friends say she was 'very thin' in the days leading to her shock passing at 79.

Further evidence of the sudden nature of Keaton's death emerged Sunday with the release of the 911 call that was made to emergency responders.

The recording, obtained Sunday by TMZ, reveals a dispatcher calling for the LA Fire Department to respond to reports of a 'person down' at Keaton's home address shortly after 8 a.m. on Saturday.

The Oscar-winning actress was transported to a nearby hospital where she was later pronounced dead.

She had been with loved ones when she passed, a relative told the Associated Press, and the family requested privacy. No further details have been released.

But close friends of the Annie Hall, Father of the Bride and The First Wives Club star recall how she had become increasingly reclusive in the past year with one longtime friend, the songwriter Carole Bayer Sager, remarking how shockingly thin Keaton had become before her shock death.

'I saw her two or three weeks ago, and she was very thin,' Sager, 81, recalled. 'She had lost so much weight. 

Sager explained that Keaton had been affected by the wildfires that ravaged Los Angeles in January.

'She had to go to Palm Springs because her house has been damaged inside and they had to clean everything.'

'She was down there for a while, and when she came back, I was kind of stunned by how much weight she'd lost,' the Grammy and Oscar award-winning lyricist shared.

Sager described her late friend as 'a magic light for everyone.'

'I just loved her,' she said. 'She was so special, she just lit up a room with her energy.'

Another of Keaton's confidantes told People that the actress' health fell off a cliff in recent months, something 'which was heartbreaking for everyone who loved her.'

The insider added: 'She declined very suddenly. It was so unexpected, especially for someone with such strength and spirit.'

'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.'

Another revelation coming out in the wake of Keaton's passing is  that her former boyfriend and costar Al Pacino had harbored a lifelong regret of not marrying Keaton when he had the opportunity.

‘Looking back, Al admits the love of his life was Diane who he’s always called, "an amazing woman,"' a confidante of the Oscar-winning actor told Daily Mail Saturday.

The friend added of Pacino, 85, 'I know he will forever regret he didn’t make his move when he had the chance' during the former duo's time together from 1971 to 1987.

'For years after he and Diane split, Al used to say, "if it’s meant to be, it’s never too late for a do-over". But sadly, now it is.'

Keaton's death was followed by emotional statements from Hollywood stalwarts such as Leonardo DiCaprio, Bette Midler, Francis Ford Coppola and a host of others.

DiCaprio called the Oscar-winning star 'brilliant, funny and unapologetically herself,' adding that 'she will be deeply missed.'

Middler said of Keaton, 'She was hilarious, a complete original, and completely without guile, or any of the competitiveness one would have expected from such a star. What you saw was who she was…oh, la, lala!'

The Godfather director Coppola said in an Instagram post, 'Words can’t express the wonder and talent of Diane Keaton,' adding, 'Endlessly intelligent, so beautiful...Everything about Diane was creativity personified.' 

The actress leaves behind an amazing legacy in Hollywood, with some of her performances in the 1970's hailed as the decade's best.

They included the titular role in the 1977 comedy Annie Hall, which was written and directed by Woody Allen, who she collaborated with on a number of memorable projects.

Keaton in 1978 would claim the Best Actress in a Leading Role award for her work in Annie Hall, her first of four lifetime nominations.

She would also receive nods for her work in movies such as 1981's Reds, 1996's Marvin’s Room and 2003's Something’s Gotta Give.

Other notable movies Keaton performed in throughout her decades-long career included 1987's Baby Boom; 1996's The First Wives Club; and the Father of the Bride films in 1991 and 1995.