Woody Allen pays tribute to the late Diane Keaton, his longtime friend and collaborator

Woody Allen paid tribute Sunday to his past romantic partner and longtime collaborator Diane Keaton, calling her the "audience of one " whose cinematic opinion was the only one he valued.

The polarizing director penned a lengthy tribute in The Free Press to Keaton, who died at age 79, her daughter confirmed to NBC News on Saturday. Keaton, who starred in many of Allen's films, won an Oscar for her role in Allen’s rom-com “Annie Hall” in 1977.

"As time went on I made movies for an audience of one, Diane Keaton," Allen wrote. "I never read a single review of my work and cared only what Keaton had to say about it."

Keaton's pre-screen critiques were so important to Allen that he'd scramble to make last-second changes to his movies before release if she seemed "less than enthusiastic" about the work.

"If she liked it, I counted the film as an artistic success," Allen wrote. "If she was less than enthusiastic, I tried to use her criticism to reedit and come away with something she felt better about.”

Allen said meeting Keaton was love at first sight.

"Unlike anyone the planet has experienced or is unlikely to ever see again, her face and laugh illuminated any space she entered," he said.

"I first laid eyes on her lanky beauty at an audition and thought, If Huckleberry Finn was a gorgeous young woman, he’d be Keaton."

In addition to "Annie Hall," the pair teamed up for "Manhattan," "Sleeper," "Manhattan Murder Mystery," "Love and Death," "Radio Days," "Play It Again, Sam" and "Interiors."

Keaton picked up Oscar nominations for "Reds," "Marvin's Room" and "Something's Gotta Give."

"She had huge talent for comedies and drama, but she could also dance and sing with feeling," Allen wrote. "She also wrote books and did photography, made collages, decorated homes, and directed films. Finally, she was a million laughs to be around."

Even after their final collaboration and the end of their romantic relationship, the pair remained close, with Keaton loyally defending Allen despite off-screen controversies that have made him a pariah in mainstream Hollywood circles.

In late 1997, Allen married Soon-Yi Previn, the adopted daughter of his longtime romantic partner Mia Farrow. He was 62 at the time, and she was 27.

One of Farrow's adopted children, Dylan Farrow, has accused Allen of sexually assaulting her when she was a child. Allen was investigated but never criminally charged.

Allen always maintained his innocence against those allegations, and he has cast himself as a steadfast backer of the #MeToo movement, which sought to bring long-hidden sexual misconduct to light.

In 2018, Keaton shared a "60 Minutes" interview Allen had given in 1992 defending himself against Dylan Farrow's accusations. "Woody Allen is my friend and I continue to believe him," Keaton tweeted.

Allen said the world is worse off without Keaton's presence.

"A few days ago the world was a place that included Diane Keaton," he wrote. "Now it’s a world that does not. Hence, it’s a drearier world. Still, there are her movies. And her great laugh still echoes in my head."