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It’s hard to imagine a greater recent modeling success than Kate Upton. After a video of her dancing at a basketball game went viral in 2011, she catapulted to the cover of Sports Illustrated and into boys’ fantasies across the globe, followed by an unfeasible leap into the pages of Vogue, despite her couture-busting curves.

She even lit up Hollywood, starring opposite Cameron Diaz in a sexy summer flick.

But, more recently, industry insiders are saying her meteoric rise has started its downward trajectory — and part of the reason for that is her own attitude.

As Upton’s career ballooned, says more than one fashion insider who spoke to The Post on the condition of anonymity, so did her ego. She went from “innocent” to exhibiting diva-like behavior, insiders say.

“She became really unappreciative of her success,” says a fashion publicist who asked not to be named for professional reasons, commenting on her general behavior. “It totally went to her head. She didn’t understand that people had taken a chance on her.”

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    Another modeling-world veteran says Upton’s demands became ridiculous, including asking for photographer approval on shoots and refusing to be photographed with other models. (She’s since posed with a male model for an Express campaign.)

    “Even Kate Moss and Naomi Campbell embrace new models and shoot with them,” the second source says. “If you look at people with those long careers, they know how to give back.”

    The secret sniping is the latest setback for Upton, 22, who’s also noticeably absent from the most recent Sports Illustrated Swimsuit issue. (The magazine did not return a request for comment.)

    As for her acting career, she has just one new project slated for production in 2015: “The Layover,” a road-trip sex comedy co-starring Lea Michele and directed by William H. Macy.

    Meanwhile, her highly anticipated Super Bowl commercial for the video game app “Game of War,” which depicted her in a medieval breastplate trotting toward a battlefield, was widely panned.

    As soon as she uttered, “Do you want to come and play?” it made people wonder whether she should have stuck to modeling.

    “This campaign does the impossible: making Kate Upton seem totally wooden,” tweeted Adweek.

    In October, Upton ditched her modeling agents at IMG Models in favor of talent agents at William Morris Endeavor to strike it big in Hollywood (WME owns IMG), according to a Page Six report. The change in management came on the heels of working with Diaz in 2014’s “The Other Woman.”

    But her range, as The Hollywood Reporter noted, was limited.

    Go to The NY Post for the full story.

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