On Friday, Charlie Brown and the gang arrive in movie theaters across the world in The Peanuts Movie, an animated film designed to reintroduce Charles Schulz's beloved characters to a new generation of kids. And while Charlie, Snoopy, Lucy, and Peppermint Patty arrive more or else as you remember them, there's one character whose presence is sure to raise eyebrows among some Peanuts devotees: the Little Red-Haired Girl.

Charlie Brown has been pining over the Little Red-Haired Girl for more than 50 years. In the full context of the series, their big-screen meeting is momentous. Though she spent decades as the object of Charlie Brown's affections, she never even appeared in Charles Schulz's original comic (with the exception of a barely glimpsed silhouette in a 1998 strip). The Peanuts Movie doesn't just beef up her role: It gives her an origin story as the new girl in town, as well as a voice, provided by 11-year-old Francesca Capaldi.

This is the biggest alteration in an otherwise doggedly faithful adaptation of the original strip. In Schulz's conception of Peanuts, the Little Red-Haired Girl is to Charlie Brown as fruit is to Tantalus. She lives in Charlie's neighborhood, and attends his school, but no matter how many times they cross paths, he never manages to say anything to her — let alone tell her how he actually feels. Like kicking a football or flying a kite, she existed, forever, just outside of Charlie Brown's reach.

The story of the inspiration behind the Little Red-Haired Girl is practically as well known as the Little Red-Haired Girl herself. In 1950, cartoonist Charles "Sparky" Schulz — just a few weeks from launching the syndication deal that propelled Peanuts into the stratosphere — proposed to the red-haired beauty Donna Mae Johnson, who he had been dating for several years. She rejected his proposal, and married a fellow suitor, Al Wold, who she had known since middle school. ''Yes, I seriously considered [marrying Schulz]," she told the St. Paul Pioneer Press in 1990. "I know I love Sparky. I guess I love Al more.''

Schulz subsequently had two other marriages, but by his own account, he never stopped thinking about his failed relationship with a red-haired girl. "You never get over your first love," Schulz said. "The whole of you is rejected when a woman says: 'You're not worth it.'" In 1989, nearly 40 years after Johnson turned down his proposal, People asked Schulz what his life might have been like if she had said yes. "Perfect," he replied.

Like so many things in his life, Schulz channeled his feelings into his comic. The very first mention of the Little Red-Haired Girl came in a November 1961 Peanuts strip, as Charlie Brown passed the time during a solitary lunch hour. "I'd give anything in the world if that little girl with the red hair would come over and sit with me," he says to himself. "I get tired of always being alone… I wish the bell would ring…" Over years and years of comics, the Little Red-Haired Girl was mentioned over and over again — an unseen presence that loomed heavily in Charlie Brown's heart and mind. He writes her succinct, sincere notes and Valentine's Day cards about how she makes him feel. He notices a bully picking on her and prepares to swoop in heroically to rescue her. He plans to win her affection by pitching a perfect Little League game.

Of course, none of those plans actually pan out for Charlie. After writing notes to the Little Red-Haired Girl, Charlie crumples them up or delivers them without signing his name. He fails to intervene on her behalf with the bully, allowing Linus to step in with his trusty blanket. And as soon as he steps onto the pitcher's mound, he gets so shaky that he can't even throw the ball, until his teammates have no choices but to lead him off the field again.

Unsurprisingly, the various adaptations of Peanuts never really figured out what to do with a character who was both so important and so elusive. The 1967 special You're in Love, Charlie Brown gave Charlie a rare triumph when she slipped him a piece of paper that read "I Like You, Charlie Brown" (signing it, bizarrely, "Little Red-Haired Girl," as if she had no name or identity of her own). A decade later, she made her first on-screen appearance in the animated special It's Your First Kiss, Charlie Brown — dolled up as a homecoming queen, complete with crown and wand, as Charlie Brown escorted her onto the dance floor.

Schulz came to regret allowing the Little Red-Haired girl to appear in It's Your First Kiss, Charlie Brown. "You have to do things that will attract some kind of attention," he told an interviewer in a conversation transcribed for the 2000 book Charles M. Schulz: Conversations. "And it's no doubt that that was one of these stupid stories we never should have done."

On one level, Schulz is completely right. We don't need to see the Little Red-Haired Girl to understand Charlie Brown's feelings for her. Peanuts is sometimes dinged for being too depressing, but when I was a kid around Charlie Brown's age, it never felt that way to me. Peanuts felt like it was channeling emotions I felt deeply, but didn't have the maturity or experience to unpack myself yet. When it came to the Little Red-Haired Girl, Charlie Brown's wild mix of terror and euphoria mirrored my own yo-yo of feelings whenever a crush was around — and for an inexperienced child, that recognition made me feel a little less awkward and alone.

When I began writing this story, this is where I thought my feelings on the subject ended. But the more I've read and thought about the Little Red-Haired Girl's arc in Peanuts, the more I've come to feel that there is something deeply sad — and even a little emotionally stunted — about Schulz's dogged and lifelong infatuation with Johnson, which extended decades after she ceased to play any meaningful role in his life.

It was only when I started to grow up that I learned that sheepishly admiring a girl from afar wasn't just self-defeating — it was totally disconnected from who that girl actually was. Charlie Brown, frozen at the same age for decades of daily comic strips, never learned that lesson.

Schulz's Peanuts, with its singular author, only tells one side of the story. But the real world isn't a comic strip, which means we also get to hear from the real Little Red-Haired Girl. Now in her mid-80s, Donna Wold, née Johnson, retains great affection for both Schulz and Peanuts — but she's never regretted rejecting Schulz's proposal. "I've had a good life," she told The Washington Post in July. "A very happy life."

Both literally and metaphorically, The Peanuts Movie gives the Little Red-Haired Girl a voice for the first time. Its message is a different one: Be a good person, and the object of your affection may come to have affection for you, too. It's a softer lesson than Schulz's, but one that's no less true — and for children who are just beginning to grapple with these strange and complicated new emotions, it may mean as much as Schulz's Peanuts once meant to me.