For Chloe Moretz, the best part was meeting Hillary

NEW YORK – It's August, but Chloe Grace Moretz arrives for lunch at the Trump SoHo Hotel shivering and tightly wrapped in a baggy black sweater over a pleated white skirt and top.

"It's cold!," says the pretty blond star of If I Stay, which opens Friday.

Perhaps, but things are decidedly hot these days for the 17-year-old actress and fashionista, who has just wrapped a string of movies and is about to film The Fifth Wave, the latest dystopian teen novel to make it to the big screen. ("I'm super hyped about it," she says of starring as heroine Cassie Sullivan.)

But first she's talking up If I Stay, based on the young-adult novel by Gayle Forman, No. 1 on USA TODAY's Best-Selling Books list for the third straight week.

Forman, who lives in nearby Brooklyn, shares the sushi and marvels at the living embodiment of her narrator, Mia Hall. In the movie, which is quite faithful to the book, Mia is in a coma after a devastating car crash. Flashbacks tell the story of her happy family life (at first she doesn't know whether her parents and little brother have survived the accident) and romance with a young rocker, Adam (Jamie Blackley).

Moretz says she read the If I Stay script and was intrigued, but really fell in love when she read the book. She emailed Forman and the two struck up an online friendship long before they met last year. The two recently bonded on a multi-city tour, where they signed books and posters and screened the movie for fans.

For Forman, who visited the set in Vancouver, Moretz was a dream choice as Mia.

"I thought 'who else can handle this role,' because really it is two separate roles," says Forman, 44, mother of two young girls. "There's the vulnerability and the falling in love and then the Mia of the accident, who's in this ghost-like state but who also has such emotionally wrenching scenes."

Moretz, who kicked some you-know-what in Kick-Ass and its sequel, says tapping into her softer side was a challenge. "I think because I'm a young actress I have issues showing emotional vulnerability, being 17. I am OK with being fierce and cool and hard, I am killing people, whatever, but when I have to show love and happiness and elation, it's scary. You're opening up a side of yourself that no one sees."

And then there was the cello. Mia is a cello prodigy who auditions for Julliard, and Moretz felt it was central to the character to take lessons. While she's hardly ready for Carnegie Hall in real life (in the movie, she says, it's "Frankenstein with my head on another girl's body"), it was all about "learning the emotion of the cello."

Moretz, who takes her craft seriously (she's been at it for a decade), is ebullient, chatty and friendly. "I can be a super mature person when I need to be and I can talk about many different things, but ultimately, when I'm with my friends, I act like I'm 12. I'm a very goofy person."

Her conversational topics whip from school (she's a senior and is tutored on set) to being obsessed with Sylvia Plath's autobiographical 1963 novel The Bell Jar ("Oh my god, I want to make it into a movie") to enjoying exploring the "dark side of my psyche" as an actor.

"I always said if I wasn't an actor I don't know if I'd be like a serial killer or something. I get it out (on film), who knows what I'm expelling," she says with a laugh.

But what really gets this effusive talker going is…Hillary Clinton?

In June, Moretz was in Toronto for the Much Music Video Awards when her driver noticed that Clinton was doing a book signing for her memoir Hard Choices. Calls were made and the young star got a few minutes with the woman she so admires.

"I cried when I met her," says Moretz, who calls Clinton an "icon."

"I've never gotten starstruck by anyone in my entire life, ever, and I couldn't breathe. She was just sitting there in her little jacket. I thought she was just going to sign my book and tell me to go but she said, 'I know the book (If I Stay), I saw it on this reader's list, and I can't wait for your movie.' "

"Hillary Clinton talked about If I Stay?," an incredulous Forman asks.

"Yes! Yes, yes, she knew the book, I was freaking out!" says Moretz. The actress and author high-five.

Did Clinton, ahem, say anything else?

"Well, I said, 'I turn 18 on Feb. 10 and I will be 18 when you run for president.' And she was like, mmmmm."

Oh well.