There's no doubt about it: Beyonce was back in full force during her special three-night engagement at Revel Beach's Ovation Hall in Atlantic City, New Jersey.

Just four months after giving birth to daughter Blue Ivy (with husband Jay-Z, 42), the 16-time Grammy Award winner returned to the stage for the first time since 2011. Equally as impressive as Beyonce's killer vocals and flawless dance moves was her jaw-dropping post-baby body.

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"Y'all have no idea how hard I worked!" the 30-year-old admitted on stage Saturday. "I had to lose 60 pounds. They had me on that treadmill. I ate lettuce!"

In May, her trainer, Marco Borges, shared more of the singer's fitness and diet secrets with Us Weekly. "We do cardio and plyometric moves like lunges and jumps on and off a bench," he said of his A-list client, who also avoids eating processed foods. "You don't have to eat only celery sticks. Be sensible and exercise constantly."

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Beyonce's dedication certainly paid off, according the design duo behind Ralph & Russo, who created the singer's curve-hugging fringe two-piece.

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"Beyonce is a true representation of the Ralph & Russo woman who is strong, powerful and independent," they told Grazia Monday. "She is an inspirational performer and creative genius, and collaborating with her is always such a fantastic experience. We had so much fun designing these outfits made with Swarovski Elements, all of which were created to provide her with a truly unforgettable stage presence."

The new mom completed her concert look with hot pink Stuart Weitzman Mary Janes.

This article originally appeared on Beyonce's Sexy, Curve-Hugging Concert Costume: All the Details!