Carl Bernstein — the famed former Watergate journalist — smiled and seemed relaxed as his son, Jacob, who writes for The New York Times and directed the film, a loving, poignant tribute to Ephron, gave opening remarks. The crowd included Ephron friends/luminaries, Rita Wilson, Kate Capshaw, Barry Diller, Diane von Furstenberg and Gay Talese. The New York Post earlier reported that Carl Bernstein didn’t agree to be interviewed “until the eleventh hour,” causing his son to scramble to finish the film. A publicist for the film said, “That is true. Carl was the last interview. And Jacob is truly glad he participated.”

The Sleepless in Seattle filmmaker, who died of leukemia at age 71 in 2012, began her extraordinary career as a gutsy, self-deprecating and sometimes ruthless journalist, abiding by her screenwriter-mother Phoebe Ephron’s Golden Rule: “Everything is copy.” So when she discovered that Carl, her second husband, had cheated, Ephron transformed the ordeal into the bestselling roman a clef-turned-novel Heartburn, which became the eponymous film starring Meryl Streep and Jack Nicholson with Mike Nichols at the helm. “In writing it funny, she won,” the late Nichols told Jacob.

In his cameo, Carl Bernstein said Mike Nichols actually signed the divorce papers for Ephron — he and Ephron were close friends, and he was directing Heartburn at the time. “It was the craziest divorce ever,” Bernstein said. At another point in the documentary, Carl Bernstein reveals to his son that he was anxious about Heartburn shaping Jacob’s image of him. “For a while it did,” replies the younger Bernstein.

Also making appearances in between archival footage of Ephron’s TV appearances and audio commentary: actors Reese Witherspoon, Lena Dunham and Meg Ryan, each reading passages from Ephron essays; Steven Spielberg who admitted, “I always wanted her to like me;” Diller who recalled with good humor how Ephron fired him from their high school newspaper; and her sister Delia, with whom she collaborated on Sleepless and You’ve Got Mail. She mused that Nora “was the Don” and husband Nick Pileggi “the consigliere” in their long and happy marriage.

In remarks following the screening, Jacob said his stepfather, who wrote the screenplays for Goodfellas and Casino, did not participate in Everything Is Copy because he “had feelings about talking about her onscreen.” He said his younger brother Max, a musician, also “wanted to keep what he had with her private,” and “more power” to others who similarly refused. The film went into production in summer 2013, with collaborators including veteran documentary editor Bob Eisenhardt, of 2008’s Valentino: The Last Emperor, which Jacob cited as inspiration for his star-studded tribute to his mother.

Perhaps the most moving moments occur when interviewees including her friends Nichols, Meryl Streep and gossip legend Liz Smith address how Ephron, so candid on the page, kept secret her illness until the very end of her life. Streep felt ambushed by the news. Nichols recounted “odd silences” while sharing a meal together before her death, adding: “I was too stupid to realize it was goodbye.” Smith offered one explanation: “She did it because she was a control freak.”

The movie does not sugarcoat Ephron’s personality — her friend Barbara Walters says, “I thought she was very funny and very mean” — though several of its subjects suggest she mellowed somewhat through the years.

“She was really fearless and … bitchy in a delectable way,” said Jacob. “If you tried to do that, you would be unhirable.” He noted, “you’d be MoNique and Alec Baldwin.” The audience roared. Like mother, like son.

Erin Carlson is a journalist who writes about the entertainment business and has worked at Hollywood Reporter and the Associated Press. She lives in San Francisco.