With her brazen brand of humor, Amy Schumer has become comedy's latest It Girl, thanks in no small part to her outlandish and satirical sketch show "Inside Amy Schumer." Now, finally, after months of foreplay, audiences will finally get to see her Judd Apatow-helmed sex comedy, which won tons of buzz at SXSW. And I'm pleased to report "Trainwreck" lives up to the hype, being deeply charming and uproariously funny.

Schumer stars as the titular trainwreck named (funny enough) Amy. She's a New Yorker who has a cool job (reporter for the barely fictional men's magazine S'NUFF), a great apartment (complete with friendly homeless neighbor Dave Attell), fun friends and a loving family made up of her married suburban sister (Brie Larson) and her drunken, ever-belligerent Mets fan of a father (Colin Quinn). As for sex, she's getting it on the regular thanks to an enthusiastic line of would-be boyfriends. But the idea of a committed relationship makes Amy turn to her one-hitter. That is until she meets a sweet sports doctor (Bill Hader in dreamboat mode) who upends everything she thinks she wants.

Setup-wise, "Trainwreck" is a pretty true-to-form romantic comedy with a genderswapped exception. Normally, it's the guy whose sleeping his way all around Manhattan until his head is turned by a babe with a brain. It's a bit disappointing that such a turnaround still feels subversive in 2015, but Schumer slays at playing the heartless playgirl whether she's maneuvering a one-night-stand into oral sex (then pretending to fall asleep before she can reciprocate) or panicking when this dreamy doctor dares to call her the morning after they hook up. Basically, it's Schumer--who also wrote the screenplay--who makes this formula feel fresh.

Of course, she has help in adding some sizzle and sparks, thanks to a cast positively stuffed with talent and stars. Daniel Radcliffe and Marisa Tomei drop in for an odd but rewarding bit. Randall Park, who killed it as Kim Jong-un in "The Interview," pops in to add some punch to a string of office scenes along with "Saturday Night Live"s Vanessa Bayer and "Parks and Recreation"s Jon Glaser ("You've been Jammed!). In a disorienting twist, the ever-glorious Tilda Swinton shares screen time with her former nightmare son of "We Need To Talk About Kevin," but this time Ezra Miller is all smiles and cheerfulness--until things get dirty…and downright hysterical.

A slew of stand-ups, from Mike Birbiglia to Nikki Glaser and Bridget Everett, make appearances that will thrill comedy nerds. Sports fans will squeal over cameos from stars like Amare Stoudemire, but it's John Cena and LeBron James who prove solid standouts, with the former making his huge body a terrifying punch line and the latter proving a pitch-perfect ever-eager bestie to Hader's romantic lead. Seriously, James is so good you should expect to see him in more Apatow movies soon.

Another tried and true advantage to this rom-com formula is that it's ripe with opportunities for sensational set pieces, like the ultimate walk of shame involving the Staten Island ferry, and a heartwarming but hilarious finale in the heart of Madison Square Garden. "Trainwreck"s only true fault is one we've come to expect from Apatow the director. Clocking in at 125 minutes, the film falls prey to Apatow's indulgences, meaning scenes run on longer than they need to, reaching for that one last joke. While sometimes that lingering gag feels worth it, overall it makes for pacing that clunks along, and transitions that feel foggy in how much time has passed.

Clunkiness aside, "Trainwreck"s bawdy jokes tackle sex and the trickier aspects of relationships with a keen wit and a sailor's diction. Simply put: I laughed so hard my face hurt. Yet for all the cynicism its heroine starts out with, the film itself is vibrant with warmth and sincerity, making for a summer movie that is a total delight just for adults.

"Trainwreck" opens July 17th.