Inside the Intimate Details of Diane Keaton and Woody Allen's Relationship... as Actress Always 'Believed' in Co-star's Innocence Despite Disturbing Sexual Assault Allegations

Diane Keaton and Woody Allen's close bond lasted a lifetime, with the director being left shattered following her death.

RadarOnline.com can reveal all you need to know about Keaton and Allen's relationship.

After they began dating in 1970, Keaton and Allen decided to live together in the latter's New York penthouse.

Although their romance eventually fizzled out, the two remained friends and collaborators.

In a 1996 interview with The New Yorker, the actor-director confirmed he also dated the star's sisters, Robin and Dory.

"I became interested in [Diane] and interested in her sisters and her mother as people," said Allen.

The What's New Pussycat? actor echoed a similar statement in his 2020 memoir, Apropos of Nothing.

"I dated her beautiful sister, Robin, and we had a brief romance. After that, I dated her other beautiful sister, Dory, and we had a little fling," he penned. "The three Keaton sisters were all beautiful, wonderful women. Good genes in that family."

Keaton and Allen's romantic relationship ended, but their friendship and creative partnership continued afterward.

They went on to collaborate on the film adaptation of Play It Again, Sam, as well as on Annie Hall, Sleeper, Love, Manhattan, Radio Days, Manhattan Murder Mystery and Love and Death.

"I still consult her on casting sometimes or any creative problems I might be struggling with," Allen said of Keaton in his memoir.

Meanwhile, the mom-of-two told The Guardian she owed everything to the Oscar-winning director.

"He was so amazing," she said of Allen. "It always was really special to be with Woody. He was great. He was everything, and he remains (so) to me. He gave me everything. He really did. Woody made it loose. That helped me enormously."

In an interview with The Guardian, Keaton said Allen was "the strongest person" she had ever met.

"He's made of steel. And talk about a work ethic, he's one of the people that really did teach me that you have to work hard," she said. "But he wanted to. He's the most disciplined person I've known, with the exception of my dad."

Keaton continued: "But his discipline is a constant, whereas when my dad retired, I think he lost sight of what he was doing. This guy? He's going to be practicing that clarinet and touring with his band and making his one movie a year until they push him; he's never going to stop. Who in the history of movies has done that? He's 78, he makes a movie a year, and he has total control. How is that possible?"

When asked about the child molestation allegations against Allen, Keaton firmly declared she had nothing to say except: "I believe my friend."

She also shared a tweet to defend him against the backlash.

"Woody Allen is my friend and I continue to believe him," said the actress. "It might be of interest to take a look at the 60 Minutes interview from 1992 and see what you think."

After Keaton's death was announced, an insider told People the Take the Money and Run star "is extremely distraught and surprised and upset" over the news.

"It makes him think of his own mortality," the source added.

Keaton and Allen remained friends for almost six decades, and he reportedly "appreciated her very much."

The insider added he was unaware of Keaton's declining health before her death.

"Nobody seemed to know. He was surprised," the source continued.