During the fight to save the Ambassador Hotel in the mid-2000s, Diane Keaton became a prominent voice for the L.A. Conservancy. (photo courtesy of the Los Angeles Conservancy)

In her Oscar-winning performance as “Annie Hall,” Diane Keaton asks, “What’s so great about New York?” Her character, like the actress herself, is an L.A. girl. No one may have been more of an Angeleno than Keaton, who was born here.

In the days following her death on Oct. 11, residents posted stories about seeing her everywhere from standing in line for the Groundlings to walking down the street in the Miracle Mile. She typically donned a wholly original outfit – sometimes in that Annie Hall vein, often with a statement hat and always in black, white or, on occasion, brown.

During the last two decades, Keaton became involved with Los Angeles Conservancy. The conservancy works to preserve historic properties throughout the Los Angeles area. By the time she joined as a board member in 2002, she had already bought and restored historic homes in some of the city’s most storied areas, including on Roxbury Drive in Beverly Hills.

“Little by little, we kind of made the connection and asked her to join the board, which that doesn’t always happen in terms of celebrities having the time and wherewithal or desire to be part of an organization like ours, and she was more than willing,” L.A. Conservancy president Adrian Scott Fine said.

There were two particularly high-profile efforts underway during the early-to-mid 2000s. One of which involved the Ennis House, the Mayan Revival home in Los Feliz designed by Frank Lloyd Wright, who had also been the architect behind one of Keaton’s homes. With the Ennis House, one of L.A.’s most unique and frequently filmed, in disrepair, an advocate at the level of Keaton was necessary to rope in the necessary funds to take over and restore the home. Along with the National Trust for Historic Preservation and the Frank Lloyd Wright Building Conservancy, the L.A. Conservancy was able to establish the Ennis House Foundation, whose board Keaton also joined. Now, the home stands – not just alive, but retaining all its original glory.

“She really did lend her name and visibility to really important advocacy issues at that time for the conservancy, which was incredibly generous for her,” Fine said. “Then it just continued from there. In terms of when we needed her, if she was available and she cared about it, she would, attend or use her name to get leverage [and] help on an issue.”

The other mid-2000s project did not have as happy an ending. At the time, the famed Ambassador Hotel was the subject of a battle between the conservancy and the Los Angeles Unified School District, which had obtained the property. Keaton led the effort to preserve the building and incorporate it into any school that might be built.

While its operations as a hotel had ceased in 1989, the property had the iconic Cocoanut Grove nightclub, where numerous Oscar ceremonies had been held and, infamously, Robert F. Kennedy was shot. The sprawling hotel had been a Hollywood playground during the Golden Age, and even as it sat dormant, it became a frequent filming location for movies such as “Catch Me If You Can,” “Forrest Gump” and “That Thing You Do!”

As the site was demolished, the conservancy held a wake on Feb. 2, 2006, in which Keaton spoke about the shock of driving on Seventh Street and seeing the shell of the Ambassador Hotel in a state of destruction.

“The dark silhouette etched in the late afternoon sky was filled with rectangular patterns of light slicing through my window pane, and I swear to you – under the aura of this almost otherworldly atmosphere – I finally recognized that I was looking at the shadow of our once glorious Ambassador Hotel,” Keaton said. “Like losing a lover, I felt that familiar … pounding heartbeat kind of racing through my body, and I felt the loneliness of her last stand. I felt the shock of what little remained in comparison to what once was. And for the first time in a long time, I felt the death of our loss. As I turned away … I even felt that I heard an echo, an echo, and maybe it was the echo of the Ambassador calling me. It was almost as if she was saying to me, ‘Goodbye, Diane. Keep me in your heart, and next time, try harder. Don’t let my loss guide you into the passive arms of apathy.”

So, while Keaton, in the dreams of a million movie goers, might be in any number of places – New York City often, as in “The Godfather” or “Baby Boom” or “The First Wives Club” – her heart was always squarely in L.A.

“She always had this sense of passion for what we were doing,” Fine recalled. “Everything you probably heard about her in terms of what you think she [was] is very much who she was … I think she has a legacy in so many different aspects of her career and who she was as a person. The preservation was definitely one of those aspects that may not be as well known, but it is something that she was passionate about, cared about. She wouldn’t have been with us that long if she didn’t care about the history and historic places and the architecture and design of Los Angeles. I think absolutely that’s a fitting way to kind of memorialize and pay tribute to who she was and what she cared about.”

“I will fight as hard as I possibly can for all those other Ambassadors out there waiting for the axe to fall in silent dread,” Keaton concluded at the legendary hotel’s wake.

To learn more about the L.A. Conservancy, visit laconservancy.org. For another chance to enjoy Keaton on the silver screen, check the showtimes at AMC Theaters over the next week for limited rereleases “Annie Hall” and “Something’s Gotta Give.”