"It was like summer camp," Wolff, 20, told PEOPLE of the cast at the film's New York premiere Tuesday night. "I mean, it was one of those few times … Everyone says it on every movie that they became a family, but you can see we just love each other, and it's one of those things that needed that way to be, and it ended up working that way."
Based on the bestseller by The Fault in Our Stars author John Green, Paper Towns follows Orland high school senior Q (Wolff) and his pals as they hunt for the enigmatic Margo (Delevingne), Q's longtime crush who goes missing at the end of the school year – and grow closer in the process.
"I mean, how could you not become friends with those guys? They're like some of the most amazing people I've ever met: extremely talented, wonderful people. What more could I ask for in a group of people?" adds Delevingne, 22, who made her debut as a leading lady in the YA-based flick.
Wolff notes that he and model-turned-actress Delevingne hit it off right away.
"As she walked in the room, it was like there was kind of a jolt," noted Wolff, who, with his brother Alex, wrote and recorded a song for the movie's soundtrack. "I think we're both similar actors. We like to be spontaneous and free. We don't plan everything out in our bedrooms the night before, you know?"
Director Jake Schreirer says the team's friendship between takes was imperative to the film's credibility.
"The only thing we really tried to do outside of filming was have everyone live in the same apartment complex so those bonds and those friendships would really form, and everyone would feel insulated and together in that way," says Schreirer.
Sure enough, per the stars' social media accounts – and a bunch of behind-the-scenes clips online! – the offscreen camaraderie came easily.