The “first wives club” actress died of pneumonia at age 79 on saturday, oct. 11 of pneumonia, according to people magazine, which cited a statement from the actress family, which also expressed thanks for the extraordinary messages of love and. Is diane keaton dead or still alive? 11, her family told people in a statement wednesday. · keaton , 79, died on oct. · as tributes continue to pour in for legendary actor diane keaton , her official cause of death has been revealed in her death certificate as primary bacterial pneumonia. · hearts were crushed around the world when news broke that hollywood legend diane keaton had passed away on october 11 aged 79. · matt stevens reported from los angeles and derrick bryson taylor from new york. · new details have emerged surrounding diane keaton ’ s tragic death at age 79 on oct. Diane keaton ’ s cause of death has been revealed. What happened to diane keatons family? How did diane keaton die? How did diane keaton achieve a lot in her career? Primary bacterial pneumonia is listed as keaton’s immediate cause of death, according to a death. Diane keaton , the oscar-winning actress known for her roles in “annie hall,” “the godfather,” “reds” and other. · in a statement issued to ‘people,’ the family of diane keaton , who died october 11 at the age of 79, has revealed that the oscar winner died of pneumonia.