"This is like a dream cast," Roberts, 23, told PEOPLE Thursday at the film's New York premiere, at the Tribeca Film Festival. "It was one of those kind of lightning-in-a-bottle casts where, when we were on set, I was like, 'This really special. This isn't like a regular movie.' "
Added the actress: "James is someone [who] I've always wanted to work with … I was so nervous to meet him because I'm like, 'Oh, my god, is he going to be nice?' And he was so nice and such a great actor to work with and just a sweetheart."
In the film – which focuses on the experiences of rebellious high school students in an urban community of northern California – Franco, 36, and Roberts share a charged chemistry: Roberts's character gets caught up in a flirtatious streak with her soccer coach, played by Franco.
"It was fun," Roberts gushes about getting up close and personal with Franco. "Neither of us made it awkward, so it was great. And also, I think the fact that I was not actually 17 probably made things less weird. I was 21. I think that that kind of made things feel like we’re pretending – this isn’t real."
"You’ve definitely met this girl, and you know this guy and the parents," she explained. "You definitely have friends who have parents like that. And I think that's what makes the movie so fun to watch, because you're kind of seeing all of this unravel and relating it to your own experiences."