The autobiographical elements of “Annie Hall” were so strong, that the title character assumed the second half of the lead actress’s real name. Diane Hall took the name Diane Keaton for the stage and screen — an appropriate tribute to the great silent era comic actor/director Buster Keaton — and had some interesting dissimilarities to her best known role.

”Annie Hall” is a comic, modern day Pygmallion story. But while Diane was as shy as Annie, she was no one’s creation but her own. As was necessary in 1970s Hollywood, she latched herself onto famous, powerful men — Al Pacino, Woody Allen, Warren Beatty, Jack Nicholson, Steve Martin — but changed all of them in remarkable ways. So many career best performances were given opposite Diane Keaton. That was not luck.

One of her late career movies that is well liked, but drives me up the wall is the Nancy Meyer’s romantic comedy ”Something’s Gotta Give” which reunites her with Nicholson. Meyers is a maddening director who plays almost the entire film in close up shots, one character responding at a time … cut, now the other actor speaks over the shoulder. What a grand waste of Keaton’s skills. To be caught up in the joy of a Diane Keaton performance is to watch her play off her scene mate, matching the energy but then subtly shifting the vibe. Warren Beatty, who spent most of his career portraying a mimbo, becomes the intelligent man he really is opposite Diane. Woody Allen, who had portrayed nothing but schlemiels up until his work with her, suddenly becomes a romantic leading man. Al Pacino is restrained. Jack Nicholson tunes down the Jack and discovers his character. Over and over again, they do this opposite Diane.

It’s no accident that the great cinematographer Gordon Willis worked with Diane Keaton first on “The Godfather” and “The Godfather Part II” before becoming Woody Allen’s principal DP. Woody approached Willis at Keaton’s suggestion, and he brought to Woody Allen films something more than beautifully lit and composed scenes — he also introduced Woody to long takes. It’s in the long chaotic scenes like the classic lobster scene in “Annie Hall” where his movies become about something other than jokes, we begin to understand the depth of the relationhips.

What everyone remembers most fondly about Woody Allen’s “Manhattan” is the gorgeous black and white cinematography and the long-walk scenes featuring Allen and Keaton. Warren Beatty, who at times drove Keaton crazy with his obsessive style of filmmaking, learned in the course of the production to trust Keaton with long-take scenes, and it’s when “Reds” isn’t manically cutting from shot to shot where it breathes and the characters step out of their iconography.

One of the most interesting contrasts between Annie Hall and Diane Keaton was revealed by Woody Allen during her American Film Institute tribute. One of the running gags of the film is that Alvy Singer is neurotically obsessed with death and keeps giving Annie books about death. But in his speech at AFI, Woody reveals that Diane was actually obsessed with death, and he once tried to reassure her with something of a modern parable.

He told her to imagine getting a colonoscopy. The procedure itself, if accompanied with the right medication, isn’t all that bad — you can drift off in a pleasant, hazy reverie. He told her to imagine that death is just like that. The only problem, Woody added, is that life itself is like all the pre-opp procedures.

The fact that Diane was just as serious and just as morbid as Woody Allen tells us something important about her — she was a brilliant, underappreciated collaborator. Woody’s scripts were always tighter and sharper when Diane was in the film — and Woody called her a brilliant writer. David Lynch gave her a chance to direct a season 2 episode of "Twin Peaks," and Keaton hoped to learn some tricks of the trade from him. Unfortunately, by that point in the series, Lynch had largely checked out. Her 1995 film “Unstrung Heroes,” while not on the level of the classics she acted in, especially in the 1970s, was a very good, sadly overlooked movie. If more people had seen and appreciated it, perhaps Keaton would have gone on to direct many more movies.

We're left instead with her steady, sometimes uncredited, influence. I noted in a previous post Woody Allen's jaw dropping statement that his full filmography was created for an audience of one. Taken in that context, you can see that when Diane was most intimately involved in the movies, Woody did his best work. The more she became a trusted friend with notes, the less direct help she could provide. Woody Allen's career has drifted at times as a result.

I've seen "Annie Hall" dozens of times in my life. It becomes a bit more melancholy on every viewing and will probably continue in this direction after hearing Woody's revealed truth. The movie has always made one thing clear – Diane was the love of his life, and he knew exactly what he lost when he couldn't bend to the needs of their relationship. Nearly 50 years later, she is still the love of his life, and perhaps that accounts for the horrors that lie ahead for him and the women and girls who came into contact with him. Perhaps Woody had only one true chance at love in life and he blew it. He drfited on, had some good moments, some very bad ones, saw his reputation rise and fall.

But mostly what he left us with is one perfect expression of that love, something that could only be made with Diane Keaton's presence, inspiration, collaboration and, ultimately, co-authorship. "Annie Hall" was her movie. It always will be.