Trench coat-wearing Lloyd Dobler (John Cusack) holding his boom box over his head at arm's length, rock serenading his true love Diane Court (Ione Skye) in 1989’s “Say Anything,” remains one of the most enduring images of film romance.

Even those too young to have cranked a boom box revere the scene from Cameron Crowe’s directing debut, released 30 years ago Sunday, with Dobler defiantly blasting Peter Gabriel’s “In Your Eyes” while Court listens from her bedroom.

But a big part of what makes the scene subtly effective is the real-life apprehension both actors were feeling shooting the scene.

"That scene is like Romeo under the trellis," says Crowe. "But I have this feeling when I watch it that it’s filled with double emotion – both with the story and the actors, whose own trepidation bleeds in."

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Cusack, who was 22 at the time, got over the fear of falling into teen romance clichés even before making the movie. These fears resurfaced with the boom box bit, which came on the last day of production. Crowe had to convince him to shoot the final scene, but Cusack's resistance is still visible.

"(Cusack) thought it was too subservient. The defiance that he has when he’s doing the scene is what makes the scene great," says Crowe. "He made it work. The way he performs it, it’s just blatantly defying you to consider it cheesy. That's why he’s so heroic in that moment. He’s still doubting whether the boom box scene is going to work at all. He’s kind of fighting for the scene."

Skye was a 17-year-old making her major-film debut with "Say Anything," and admits she was experiencing feelings of a different kind, separately shooting Court's moments as she hears the music played by her first love, with whom she had broken up.

"I was young. I remember thinking I didn’t like the way that top looked or something in the scene. It’s just so silly," says Skye, "That’s what you get for being a teenager; every once in a while, it comes out with the acting."

While Skye says she "would put a little more into" the scene given the chance to do it again, her subtle unease as she listens to the music conveys Court's own emotional discomfort.

"Ione was feeling vulnerable. Her kind of nervousness brought that moment to life," says Crowe. "Lloyd is working his way into Diane's life again and Diane is nervous about it all."

Crowe admits the boom box serenade he had written could have come across "silly" if played incorrectly. But it was inspired by true emotion.

"It's when you’re at the peak of loving a song, and the song is speaking to you so loudly," says Crowe. "I thought, 'What if you take this song to the person that you’re thinking about and just listen to it with them?' But I didn’t know how it was going to turn out."

History would say, perfection. "Say Anything" and the boom box became an instant cultural phenomena. Crowe says Cusack saw that he had made the right choice in making the movie the first time he saw it. Watching it together was "emotional," and the reaction they both received walking around New York City after release was special.

"(Cusack) was getting so much love from people on the street. They were asking, 'Are you Lloyd Dobler?' And I remember him saying, 'On my better days, that’s me.' That was so full circle."

Still parodied, re-creating the boom box moment is getting more difficult. Skye found this out during a 2014 25th anniversary event filled with trench coat-wearing attendees.

"I talked to the organizer, who said it was so hard to get all those boom boxes and the coats," says Skye. "The whole thing is getting much harder to pull off."