WITH THE SAME EXAGGERATED CHUTZPAH she has brought to her stand-up act, her talk show stints and her home-shopping sales pitches, Joan Rivers is explaining what is special about Tears and Laughter: The Joan and Melissa Rivers Story, an autobiographical TV-movie memoir that will air May 15 on NBC. "True grief, true mourning, what happens after a suicide, has never been honestly dealt with before," declares Rivers. That's simply not so, as anyone who has ever seen Antigone, Ordinary People or any number of suicide-oriented TV movies of the week can testify. Yet this is almost certainly the first time the survivors of a suicide have portrayed themselves in a prime-time drama. However one feels about the final product (see review, page 22), reenacting the events surrounding the death of Melissa's father and Joan's husband of 22 years, producer Edgar Rosenberg, proved to be a wrenching experience.

Nowhere did emotions swell more strongly than in the scene rehearsed in March on a set decorated to resemble the Beverly Hills mansion where the Rivers-Rosenberg family once lived. Joan and Melissa were about to reenact the traumatic moment in 1987 when a suitcase belonging to Edgar arrived at the front door. A few days earlier, Edgar, 62, had packed the bag himself and checked into a Philadelphia hotel. There, apparently depressed over his ill health following a heart attack three years before, as well as the recent cancellation of Joan's late-night talk show, he had ended his life by consuming a fatal mixture of alcohol and Valium.

Now, on this Vancouver film set crowded with film crew members, mother and daughter felt an unexpected echo of grief. "We opened [the replica of] Daddy's suitcase," recalls Joan, "and Melissa dissolved into tears exactly the way it really happened. She couldn't stop crying." The director, Oz Scott, shaken by her outburst, suggested they wrap for the day. But Melissa, 26, who is making her acting debut in Tears and Laughter, insisted on completing the scene. "I was so embarrassed," she says, "but when I looked up and saw them all so caring and sympathetic, I said, 'This is my job.' "

It is also, apparently, her therapy, as prescribed by Joan. Melissa's mother, who has already written a book about surviving Edgar's death (Still Talking), believes that you can't rehash the painful incidents in your life too often. "People keep asking me, 'Why are you doing this project?' " says Joan. "Because," she explains, "it heals. The more you talk about anything, the better it is." Nor do the Rivers women stop at re-creating their trauma; Tears and Laughter also deals with their ensuing yearlong estrangement, during which mother and daughter did not speak.

Both Joan and director Scott call the movie cathartic. Watching the women bare their souls on-camera, Scott says, "I felt emotionally drained at the end of the day. Bui," he adds, "I think there's still stuff to let go." Joan agrees. "There were many closets that were never opened," she says, "nor will they be."

The suicide itself, for example, is never depicted. "I was the one who said 'no way' to that," says Melissa, "and my mother backed me 150 percent. What went on in that hotel room is his business only." In fact, Edgar is not seen at all in this movie; no actor was cast in the role. Nor is his suicide note read, at least not verbatim; at the last minute, Joan insisted on making minor changes in it. "To read his words out loud is very difficult," she says. "I could barely do it."

Both women maintain, however, that they are making progress in getting over the pain. Joan, at 60, has never been more active. On May 5 she opened on Broadway, playing the title role of Lenny Bruce's mother in the comedy Sally Marr...and Her Escorts, which she cowrote. Meanwhile, she continues to hawk her line of costume jewelry on cable's QVC channel and to serve as host of her syndicated talk show, Can We Shop? Melissa, a feature correspondent for CBS This Morning, is developing a TV talk show with Madonna's production company.

Romance is also in the air. For the past year Melissa has been dating John Endicott, 28, an L.A. show-horse trainer. And Joan, too, has a beau, whom she declines to name because, she says, "he is very, very private." She herself divulges that "I'd like to get married again [someday]."

Sometimes, though, it almost sounds as if she still is. "I still get angry," says Joan. "I walk by his picture and say, 'Why aren't you here?' But the majority of the anger has passed for me. I am very, very happy—so lucky. My husband knew me so damn well. He said that I was a survivor."

LYNDA WRIGHT in Vancouver