Although BookCon 2015 featured appearances galore by Hollywood celebrities, the Paper Towns panel on Saturday evening surely was the highlight of this year’s literary fanfest for the raucous crowd of 2,250 that filled the enormous Special Events hall.

Applause greeted the panelists as they stepped out onto the stage to join the moderator, Kathleen Heaney of Elvis Duran and the Morning Show, with the ecstatic roars directed towards John Green filling the hall as he waved to the audience before taking his seat. Despite the presence of two young Hollywood actors who star in the movie – Nat Wolff (Quentin) and Justice Smith (Radar) – the hour-long event was a lovefest between Green and his fans from beginning to end. One young woman sitting near the front shouted before the discussion kicked off, “I love you John!” prompting him to respond, “I love you, too.” And when Heaney asked the audience – mostly teenaged females, with a sprinkling of young men – who had read the book, most of them raised their hands and/or whooped in response.

Paper Towns’ director Jake Schreier, screenwriter Michael H. Weber, and music composer Ron Lott rounded out the panel. Brien McDonald of ReedPOP, which puts together BookCon’s schedule of events, told PW that Cara Delevingne, who plays Margo, the female lead, had been invited to participate on the panel, but, due to her shooting schedule, had been unable to do so. Although Green did not mention on-stage the panel’s lack of women, he did apologize later on Twitter for the lapse and promised that “it will not happen again.”

After the audience watched an exclusive movie trailer scheduled to air on June 2 during the TV show Pretty Little Liars, the panel discussed how the movie adaptation differs from the book without giving away any real spoilers, except for Schreier’s announcement that Green would make a cameo appearance in the movie (his cameo in The Fault in Our Stars had landed on the cutting room floor). Green seemed just as surprised and delighted at the news as the audience, joking that the director had told him when he taped it that it was a “useable” performance. Green also said that he felt that he had “reached out very broadly” and “got very deep” into the role, which is non-speaking and lasts just a few seconds.

Paper Towns will premiere nationwide on July 24, while the soundtrack will be made available on June 16.

Green and Weber both emphasized that what mattered most to both of them was transferring to the screen central themes that were essential to the novel. “I just want it to be a good story and to capture the themes,” Green declared. “I’m more concerned about preserving the themes.” Weber explained that he had “figuratively and literally taken apart the book” – in a print-out fomat, he hastened to add when Green expressed some surprise at such sacrilege. He noted that he and his team were working with a novel that fit into several genres and had to make the story flow on screen. Thus, he said, he tried to remain faithful to the book, but he also tweaked Green’s original tale to make for a better movie.

“It’s a balancing act and a process,” Weber said, while Green explained that during the process, he was “more prone” than anyone else to suggest that the screenwriters take liberties with the script, as he doesn’t “take ownership” of his books. It’s a personal philosophy that he expanded upon later in the hour, saying at one point, “Books do belong to their readers. I have to let it out into the world and let it do what it’s going to do and mean what it’s going to mean to people.”

It was clear during the discussion that the central theme of his novel – that a person would put another person he or she doesn’t really know on a pedestal, as Quentin does with Margo – is very important to Green on a personal level. “We do girls a disservice by putting them on a pedestal and romanticizing them,” Green said, recalling how he teared up during Delevingne’s audition, which included a scene between Quentin and Margo, when Quentin says “I love you” and Margo says, “What? You don’t even know me.” Green noted that he hadn’t known that Delevingne “was famous” during her audition, but that she had nailed the character, probably because the actor, who is also a model, knows what it’s like to be placed on a pedestal.

"Treating a person as a miracle is always a mistake," Green said.

Green also gave shout-outs to actor Jaz Sinclair, who plays Radar’s girlfriend, declaring that he thought the character as Sinclair portrayed her was more interesting than his original character in the book. Sinclair “brought that character to life so much,” he said. And he noted that actor Halston Sage (Lacey) also brought added complexity to a character whom audiences think they know and then realize they really don’t.

Schreier probably summed up best during the reunion between Green, and the Paper Towns cast and crew why there was such an obviously genuine camaraderie among all of the panelists. He’d never been involved before in a project in which “literally, everyone was in it for the right reasons,” he said. Every person affiliated with the movie “wanted it to be the best possible movie,” and one that would “live up to [Green’s] book.”