TORONTO (AP) — Does Hailee Steinfeld know how good she is?
It's a question writer-director Kelly Fremon Craig and producer James L. Brooks would often ask themselves after watching the young actress shoot a take while making their high-school comedy "The Edge of Seventeen."
"Jim and I would sit there and go, 'Holy god!'" says Craig. "And after we'd call cut, Jim and I would be staring at each other with our mouths open and she'd just be on her phone like she didn't even know she did something that great."
Steinfeld, an Oscar nominee at 14, is having another breakthrough at 19. In Craig's much-lauded directorial debut "The Edge of Seventeen," the young star of the Coen brothers' "True Grit" proves that she's matured into one of the finest (and funniest) actresses of her generation.
It's a comic and heartfelt coming-of-age movie in the John Hughes mode in which Steinfeld stars as Nadine, a Job-like high-school junior plagued by a series of embarrassments. She's a self-described "old soul" who resents her fellow high-schoolers as "mouth breathers"; she's equal parts narcissistic and self-loathing, and altogether witty, honest and original.
"This was one big liberating role for me," Steinfeld said in an interview earlier this fall. "It was amazing to be able to express all of that because I feel like, in a way, I haven't really been able to before. This character is so much like myself."
Steinfeld was making a brief stop at the Toronto International Film Festival, where "The Edge of Seventeen" (in theaters Friday) was the closing night film. It was brief because in between acting, Steinfeld is trying to become a pop star; in Toronto, she was in between concert stops, fresh from Radio City Music Hall, on a tour as the opening act for Meghan Trainor.
Music, she says, was always part of her plan. The transition was partly enabled by her singing turn in 2015's "Pitch Perfect 2." Shortly after its release, Steinfeld landed a record contract and put out her first EP, "Haiz," last November. Steinfeld, a pal of Taylor Swift's (she appears in Swift's "Bad Blood" video), has had some success; her single "Starving" got up to no. 14 on Billboard.
"It's definitely something that requires going in headfirst and not looking back," says Steinfeld. "When you stand on that stage, it's you. It's me going out there and being vulnerable in front of a bunch of people and having fun. And it's scary because it's so different than having that protection of being a character."
The irony is that Steinfeld, in character, is such a genuine performer and potent force of nature.
That was first evident in "True Grit," Joel and Ethan Coen's Charles Portis adaptation in which she played the scripture-quoting, pigtailed Mattie. The Coen brothers searched and searched for an actress for the part before finding the then 13-year-old Steinfeld; she was the only one could handle Portis' ornately formal dialogue.
Steinfeld vividly remembers the Coens giggling at the spot-on precision of her audition. In her feature film debut, an uncanny command of language came naturally.
"I would get the feeling that I was in it, that I had switched on. But I never got the feeling that I switched off," she says. "In a way I felt like I had control but at the same time didn't know where it was coming from."
The experience of "True Grit" remains unmatched for Steinfeld, she says; rare are directors who so trust actors. She was among the youngest every nominated, but after the Oscars, life more or less went back to normal.
"I remember a lot of people telling me: 'Your life is about to change, so much is going to be different, blah blah blah.' After it all kind of settled down I was like: Nothing's different. I have no idea what people are talking about. I'm still me, waking up in the same bed," says Steinfeld, who grew up in Los Angeles.
Her next film didn't come out for more than two years. She has since done Shakespeare ("Romeo & Juliet"), YA ("Ender's Game") and thrillers ("The Keeping Room"). But it wasn't until Craig and Brooks, after auditioning a thousand other girls, that Steinfeld found her next great part.
"We almost didn't believe our eyes," says Brooks. "Suddenly we had a movie."
With Brooks ("Terms of Endearment," ''The Mary Tyler Moore Show") serving as her mentor, Craig set out to capture a more realistic view of high school, interviewing dozens of teenagers. But it all depended upon finding the right Nadine.
"Hailee can just turn it on in a way that I've never seen anybody be able to do before," says Craig. "There's an effortless to it. At least it looks very easy for her, which in a way makes you feel like you're witnessing some type of magic."
Her rapport with Woody Harrelson (who plays a sardonic teacher) is so good that Brooks says, "They'd be doing Tracy-Hepburn movies together the rest of their lives if he was younger."
"I feel Hailee can work and make movies for the next 50 years," Brooks says.
Follow AP Film Writer Jake Coyle on Twitter at: http://twitter.com/jakecoyleAP