American filmmaker Woody Allen is "extremely distressed" by the news of actress Diane Keaton's death

American filmmaker Woody Allen is "extremely distressed" by the news of actress Diane Keaton's death, who passed away on Saturday in California at the age of 79, a source revealed to People.

"He is extremely upset, shocked, and saddened," assured the source, who added that the passing of Keaton, with whom Allen shared a long friendship, "makes him think about his own mortality." As explained, the filmmaker was unaware of the actress's health decline. "No one seemed to know. He was shocked," they said.

Allen and Keaton met in the late sixties when she auditioned for his play 'Play It Again, Sam.' They had a brief romantic relationship, after which "they remained friends" for the six decades following the romance, the source recalled. "He thought the world of her," they expressed.

Throughout their careers, the two collaborated on eight films, including the legendary 'Annie Hall' (1977), which earned Keaton the Oscar for Best Actress, as well as 1979's 'Manhattan.'