Ryan Gosling as Jacob Palmer and Emma Stone as Hannah Weaver in ‘Crazy, Stupid, Love’.Credit : 

Ben Glass/Warner Bros.

Emma Stone was unfazed during her audition for Crazy, Stupid, Love.

Speaking with PEOPLE as the film celebrates its 15th anniversary this year, directors Glenn Ficarra and John Requa remember how the actress, now 37, stood out from the other contenders to play Hannah Weaver.

“We had this whole thing with Emma where it was really difficult to get an audition from her. And she was living in New York at the time, and I don’t know if she was busy or whatever. But we finally got her to read and she was fantastic,” Ficarra recalls.

“So we put her together with Ryan [Gosling]. We did this whole day of actresses reading with Ryan, and a lot of them were really good. But then, once Ryan stepped into the room, they sort of were a little shaken,” he explains, noting that Gosling, “Wasn’t trying to do anything. He was just being himself.”

“And then Emma came in and Ryan said a line and he flubbed the line. He was reading with her offscreen, flubbed the line, and Emma just, without missing a beat, was like, ‘Oh, you’re killing this. You’re doing great,’ ” he laughed. “She just flipped him the shit right then and there, and we were all just like, ‘Okay, that’s it. That’s the person.’ And we wanted to work with her desperately. Even in the small stuff she was doing, she’s so brilliant.”

The 2011 film starred Steve Carell as Cal Weaver, a middle-aged man newly navigating divorce from his wife (Julianne Moore) and rediscovering confidence with the help of a newfound friend (Gosling). Stone played one of the couple’s three children, with Jonah Bobo and Joey King rounding out the bunch.

The chemistry between Stone and Gosling, now 45, is one of the shining elements of the film. Ficarra says one of the scenes that best displays their chemistry is where the two set out to spend a raunchy night together, but end up chatting in bed and getting to know each other instead.

“I would say that Ryan and Emma and falling in love, montage in bed, which was a really improvised thing that I think only me and John really understood what we were doing there. And just sat there with the cameras rolling for hours and letting them just run,” he shared.

“Many of those lines in that scene are stuff they were doing around the set. They were just watching YouTube and seeing things, and then Emma would do an impersonation. And we just kept saying, ‘Do that thing you were doing when we were standing over in video village the other day. Do that thing.’ And the crew and the actors thought we had lost our minds,” Requa recalled.

“Everybody was just like, ‘I don’t know what you guys are doing,’ but we were just trying to get them to be Ryan and Emma and not their characters and just relax a little bit,” he noted, adding, “When we went into the editing room to see the first cut of that scene, and it’s basically what’s in the movie. We didn’t really have to change it.”

Ficarra credits not just the actors, but editor Lee Haxall, for bringing the scene together. He adds, “It was all very organic and cool. But it took a long time, but it paid off.”

Ryan Gosling and Emma Stone in ‘Crazy, Stupid, Love’.

Ben Glass/Warner Bros.

As the film celebrates its 15th anniversary, and Gosling and Stone have gone on to work together in two other films, Requa shared that the duo is “extremely proud” of what they brought together.

“People oftentimes say, ‘You’re good at finding actors.’ We always like to say, it’s like saying the sun is bright. They were just amazing. It was easy,” he shared, noting, “They were just brilliant and it was obvious.”

Crazy, Stupid, Love is now available to own on Blu-Ray & Digital.