'The Fault in Our Stars': 11 Things to Know Before Seeing the YA Tearjerker

Twentieth Century Fox
"The Fault in Our Stars"

THR previews the Shailene Woodley-Ansel Elgort starrer with a breakdown of the real-life inspiration and cancer diagnoses, plus the pages and footage left on the cutting-room floor.

The Fault in Our Stars hits theaters Friday, and while devout John Green fans have been anticipating the release date since the book was first published in 2012, a slew of those who haven't read the book have nevertheless purchased their tickets to the top-selling love story in Fandango history.

Still, many others have no idea what all the Fault fuss is about.

PHOTOS: Shailene Woodley, Ansel Elgort Fete Love Amid Cancer at 'Fault in Our Stars' Premiere in NYC

The Hollywood Reporter breaks down what viewers -- especially those who haven't read the best-selling YA novel -- need to know about the film, including its real-life inspiration and characters' cancer diagnoses, plus the pages and footage left on the cutting-room floor:

1. Shailene Woodley's Hazel Grace Lancaster has thyroid cancer with metastasis forming in her lungs, which causes her to carry around an oxygen tank and wear a cannula, and occasionally she has trouble breathing. "I thought a lot about it, and after meeting with people who they themselves were stuck with an oxygen tank 24/7, I realize that if I were to actually breathe the way Hazel, if she were a real person, would breathe, it wouldn't translate visually to the screen," she said, shortening her breath while answering. Read more about Woodley's approach -- plus the cast's favorite lines from Green's novel -- here (and read why she isn't wearing a sundress in Amsterdam here).

2. Ansel Elgort's Augustus Waters had a type of bone cancer called osteosarcoma, but is in remission after having part of his leg amputated -- a demanding special effect. "We used Ansel's performance on set as the basis for how his prosthetic leg should be moving, and we used a young man who actually lost his leg as a double and for lighting reference," said visual effects supervisor Jake Braver. "Ansel really sold those shots with his performance." Read more about the Fault visual effects here.

3. Nat Wolff's Isaac had to have one of his eyes removed due to a tumor, and throughout the course of the film, loses his sight completely. "I didn't want to have to fake being blind if I didn't have to, so I put these two contacts into my eyes that made it so I really was blind -- they were completely black," he explained. "Once I went blind, I always had blackout contacts and black glasses so no one could see my eyes." Read more about Wolff's dark humor and epic egg-throwing scene here.

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4. Fault was inspired by Esther Earl, a 14-year-old fan with thyroid cancer whom Green met in 2009 at a Harry Potter convention. "I had to come to a philosophical place where I believed that short lives could also be rich lives," he said. In Earl, "I saw more of the complex story that happens outside of the hospital … the richness and the fullness in her life." Green dedicated Fault to Earl, but he's quick to emphasize the difference between fact and fiction. "Her charm and snark inspired the novel, but Hazel's story is not Esther's," he says. "Esther's story belongs to her." Read THR's profile of Green here.

5. Elgort is a former ballet dancer and theater performer, and is also an EDM producer with the alter ego Ansolo. "I was at the School of American Ballet, and they put me in The Nutcracker at Lincoln Center," he said. "That was my first time performing, and it was in front of 3,000 people. I loved it." See more of the actor -- including his THR photo shoot -- here.

6. Lily Kenna, who plays young Hazel in the film, actually shaved her head during her first day on set. "It was traumatizing to me, actually -- her mother was crying, and Lily was cool," said Laura Dern, who plays Hazel's mom. Sam Trammell, who plays Hazel's dad, echoed, "A lot of her classmates had read the book, and she was going to have to back to school, to seventh grade, with that haircut. It was a big sacrifice." Read more about Dern's and Trammell's experiences playing the Lancaster parents here.

7. While many things are left out of the film -- for the sake of time, says Boone, such as the swing set-selling scene and extra characters like Gus' ex-girlfriend and Hazel's lost friend (as well as Green's cameo, for which Wolff was his acting coach) -- the Anne Frank House scene in Amsterdam was preserved. "Anne Frank is another person who died young due to circumstances that were well outside of her control, and also because it has become this place of silent reverence -- people are hushed in that museum," Green told THR. "For Hazel and Gus, it's a very different place, because it's a place where a person was alive." But not everyone is pleased with the parallel. Read what critics are saying about the film here.

8. Fault is the second of three films in which director Josh Boone works with Wolff; Boone first cast Wolff in his directorial debut Stuck in Love and is currently writing a part for him in The Stand, based on Stephen King's epic. "He's a wonderful improviser, he's my secret weapon, my lucky rabbit's foot," Boone said of Wolff. "Two or three of the biggest laughs in my first movie, he improvised. He's gonna be in every movie I make." Read more about their third film together here.

PHOTOS: Photos of 'Divergent,' 'Fault in Our Stars' Actor Ansel Elgort

9. The Swedish hip-hop genre that reclusive author Peter van Houten (Willem Dafoe) plays for Hazel and Gus is actually Green's personal favorite. "The only band I listen to is the Mountain Goats -- the last time I heard new music was like, 1996. I’m a very old person," said Green, who added that he loves Ed Sheeran's "All of the Lights" track. Read more about Sheeran's soundtrack contribution here.

10. What's the secret behind the electrifying chemistry between Woodley and Elgort? Divergent. "There's something really beautiful about working with someone and working with them again and again and again, because the more you get to know somebody on a personal level, the more free you feel artistically. I think that if Ansel and I hadn't known each other from Divergent, our relationship in this movie would not be what it is, because we didn't have to go through the rehearsal phase of getting to know one another, becoming comfortable with one another," said Woodley. Read more about why the actress idolizes Hazel -- and why Boone initially refused to cast Woodley -- here.

11. Fault could have ended in Mexico. Said Green's longtime editor, Julie Strauss-Gabel, "Y'mean the whole Mexican warlords and the drug running and that stuff? All books reach a point, especially at the latter stages, where authors don't want to walk away. There was a moment where he had particularly colorful ideas on how to end the story." Green added, "Oh God, the ending was, um, the ending of the first draft was this epically terrible case where Peter went out and went on a road trip to Mexico. I don't even want to talk about it. When Julie read the whole draft she said, 'This is by far your most interesting and ambitious novel, but I can't tell if the last 50 pages is a joke!'" Read more about Green's writing habits -- including secretly signing books, weaving death into his stories and looking to the '80s for inspiration -- here.

[Bonus: bring tissues. Even Woodley cried.]

The Fault in Our Stars hits theaters June 6.

Email: Ashley.Lee@THR.com
Twitter: @cashleelee