Trainwreck — presented Sunday night at SXSW in Austin as a “work-in-progress” — is a triumphant two-hour big-screen comedy that’s the best thing that could have happened right now for its star and writer, Amy Schumer, as well as its director, Judd Apatow.

If timing remains the secret to successful comedy, then thank Howard Stern for inviting Schumer to his radio show when he did — that morning’s sit-down brought Schumer to Apatow’s attention, which led to them meeting, which then led to their first feature film together.

And Trainwreck really delivers.

Big laughs. Heartfelt moments. Lots of juicy supporting roles for both stand-up comedians (Colin Quinn, Dave Attell, Mike Birbiglia among dozens) and all-star athletes (most notably LeBron James and John Cena) to chew up the scenery. Even Norman Lloyd, at 100 years old, gets into the act once more with some funny lines that belie his age. Since it’s billed as a “work-in-progress” with the official release date from Universal still four months away on July 17, it’s crazy to think Apatow and Schumer could make this movie even better by then.

So I asked Apatow before Sunday’s screening what one scene he was going to examine the audience’s reaction to most. “One scene? You know, none of them really,” Apatow told The Comic’s Comic. “There’s one scene that we haven’t seen in front of an audience before where Amy and Vanessa Bayer are in a bathroom debating which version of Johnny Depp they’d most like to sleep with — which movie character of all of his characters would be the best to date.”

That scene arrives early in the plot.

Schumer narrates at various points, first attempting to assure us, “I am fine. I’m in control!” then later offering meta commentary on her own “love montage” by comparing it to another New York comedian/filmmaker, Woody Allen. By the end of Trainwreck‘s happy tearjerker climax, Schumer and Apatow have proven that the question of the Bechdel Test, or even the very cliche notion of rom-coms, can be turned on its head. Trainwreck can exist as both an Amy Schumer movie and a Judd Apatow film without making you think they’re mutually exclusive. Consider this her “This Is 32.”

Or as Colin Quinn, playing a semi-autobiographical version of Schumer’s own father, tells “Amy” halfway through the picture: “You sound like a Lifetime movie. A happy one, not one of the murder ones.”

“This is a personal story for me,” Schumer told the audience inside Austin’s Paramount Theatre after Sunday’s SXSW screening. Making it alongside her sister, Kim, who “was a producer and she helped me write it a lot,” meant the world to her.

Brie Larson plays Kim in the film, while Mike Birbiglia plays Amy’s brother-in-law. Dave Attell produces gut-busting laughs in a recurring bit as a homeless guy working the sidewalk outside Amy’s apartment building. Quinn effectively opens the film in flashback, explaining his divorce via doll metaphors to young 9-year-old Amy and her little sister, then showing up later in the nursing home (where he’s battling MS) to deliver wisecracks and trade jokes with Lloyd’s “Norman” amid his fatherly advice.

The plot hangs on Amy balancing her career as a writer for a typical tabloid lifestyle magazine called “S’Nuff” run by a wickedly devious Tilda Swinton, who assigns her a profile piece on a sports surgeon played by Bill Hader that radically changes Amy’s perspective on sex, love and intimacy. Amy’s co-workers at the magazine include a slightly ditzy Vanessa Bayer, Jon Glaser assuming his best misguided overconfidence, and Randall Park as the guy who pitched the article on Hader’s doctor, Aaron Conners. As a celebrity surgeon, Dr. Conners brings all sorts of cameos into Amy’s world and that of the movie — especially King James as an unlikely BFF for the good doctor (How much time does BronBron spend in NYC? No matter, because he deftly shows that his multiple-hosting gigs on SNL were no fluke — the big man can bring it). All of the celebrity cameos somehow magically work.

Even the movie within the movie provides an amusing distraction, and allows one of Amy’s suitors (played with gleeful abandon by pro wrestler Cena) to get into a verbal shouting match with another couple in the movie theater, played by stand-ups Keith Robinson and Marina Franklin.

You can easily lose count trying to keep track of all of the comedians who pop up in scenes both large and small, from Jim Florentine and Bobby Kelly as one-night stands, to Tim Meadows, Kyle Dunnigan, Nikki Glaser and Bridget Everett at a baby shower (which echoes back to a great bit from Schumer’s stand-up act), to Rachel Feinstein as Dr. Conners’s nurse, to Pete Davidson as a stoned patient, to even Leslie Jones and The Comedy Cellar’s booker Estée Adoram as passengers on a stalled subway car.

Trainwreck may be Amy Schumer’s most personal story, as she said.

In doing so, it may also be her most successful one to date. Which already has me looking forward to seeing her tell the next story.

Trainwreck opens nationwide July 17, 2015. Here are Universal’s two official trailers (regular and red-band):