By Nicole Sperling
Updated March 15, 2015 at 12:00 PM EDT
Credit: Michael Buckner/Getty Images

Comedian and television star Amy Schumer made her entrée into the film world at the 2015 SXSW Film Festival in Austin on Sunday when she debuted her upcoming film Trainwreck to a sold-out crowd. A personal story about a single girl named Amy who is afraid of intimacy and quite successful at making bad choices, the R-rated film was a collaboration between Schumer and director Judd Apatow. It hits theaters this July. The comedian, whose series, Inside Amy Schumer returns for a third season on Comedy Central April 21, ditched another screenplay to work on Trainwreck. The movie explores how difficult it is to fall in love, as her character does with a sports medicine doctor played by Bill Heder. “It’s scary to fall in love,” Schumer tells EW during a joint interview with Apatow just before her film’s SXSW premiere. “I was falling in love with someone when I was writing it and it wasn’t even fun. It’s just terrifying. You’re just waiting to be hurt.” The film is also something of a family affair, with Schumer’s sister Kimberly, a comedy writer, producing. And in another plotline that hits close to home, Colin Quinn plays Amy’s dad, a man battling Multiple Sclerosis—the same disease her father suffers from in real life. “There is no denying that there is a lot of me in this movie,” Schumer says. “I, as they say, went there. It’s really personal. It’s about stuff I was struggling with and am constantly battling.” If all this sounds serious, never fear: The movie’s also full of Schumer’s trademark raunchy humor.

Trainwreck features an unlikely cast of supporting characters, including Tilda Swinton as Amy’s fiery boss; LeBron James as himself, and WWE star John Cena as one of Amy’s boyfriends. Much to Apatow and Schumer’s relief, the athletes never played the prima donna card.

“When guys show up and approach it like all the actors and comedians do, it really works,” says Apatow. “Neither John nor Lebron ever said, ‘Oh, I can’t do that, that will be embarrassing. What will my fans think?’ LeBron not once said to me, ‘Dude, I’m not saying that.’ He just went for it.” With James on set, so came his fans—including Chris Rock, who not only visited with his kids in tow, but also handed LeBron lines. “Chris Rock was pitching jokes for Lebron, all of which are in the movie, all of which killed,” Apatow says. “There is a run where he says, ‘You have to be careful because you don’t want a baby mama,’ and he goes on this run about how you handle your baby mama because before you know it, you have to buy her a pantsuit line.” “Ahh, that was mine,” Schumer pipes in. “I’ve got to take credit. The pantsuit line was mine.”