It’s not rare that characters change completely during the development of a film. From the initial draft of the script to the lines being read by an actor on set, the character can go through a ton of variations. And according to those that worked on the original “Fast and Furious” film from 20 years ago, Michelle Rodriguez’s Letty character was a completely different person from the first draft to the finished product. Because of that, her relationship with Vin Diesel’s Dominic Toretto is a fan-favorite.

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In a new oral history from EW, the actors from “The Fast and the Furious” talk about how Michelle Rodriguez was a vital part of why the character of Letty is one of the most popular in the series. Co-star Jordana Brewster said, “When Michelle [Rodriguez] read her role, she was like, ‘No, I’m not playing that.’ And then she changed it completely. It went from a trophy girlfriend to this really layered character.”

Fans of the franchise will know that Letty is a character that is just as tough and badass as any of the men in the series. And from the very beginning, though she is as beautiful as any of the other women, Rodriguez brought something special to the character that set her apart from the rest. Something that the actress said comes from reality.

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“It was a reality check for them to realize that the streets don’t work like that,” explained Rodriguez. “You don’t just get with a guy because he’s hot. There’s a hierarchy there. Can that hot guy get beat up by who you’re dating? If he can, then you don’t date him, because why would you want to lose the hierarchy? In order to keep it real, I had to school them: ‘I know you guys like Hollywood and all that, but if you want it to be realistic, this is how it really works, and I’m not going to be a slut in front of millions of people, so you’re going to lose me if you don’t change this.’ And they figured it out.”

Of course, the character of Letty was allowed to become someone different. Then when she was brought to life by Rodriguez, she became an instant hit with fans. And the on-screen love affair between Letty and Dom has grown to be at the center of the franchise. According to Vin Diesel, it’s grown even beyond the franchise.

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“One of the biggest blessings of the franchise is my relationship with Michelle,” said Diesel. “I’ve been told that the Dom-Letty love story is potentially the biggest love story that we’ve seen in cinema. After two decades, you understand that point.”

While it’s unclear if history will back up the idea that Dom and Letty’s romance is up there with the all-time greats, it’s obvious that the ‘Fast & Furious’ franchise continues to make billions of dollars and delight fans all over the world. So, Diesel may be overstating a wee bit to call it the “biggest” love story in the history of cinema, but it might be one of the most popular.

The ninth film in the franchise, aptly titled “F9,” arrives in theaters on June 25.