Britney Spears Flashes Insane Bikini Body While Hanging With Her 'Louisiana Boy'!

You better "work b**ch!"

Britney Spears has clearly been hitting it hard at the gym.

The "Work B**ch" singer shared a pic with her 4.8 million Instagram followers on Sunday that showcased her fit physique. Donning a yellow string bikini top, Spears has never looked happier posing next to a male friend.

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"So nice to be home!" the 33-year-old pop star wrote. "Nothing like Louisiana boys."

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This past December, Spears shared some of her workout secrets to Women's Health. "I start with 20 minutes of intense cardio -- usually running -- move on to light free weights, body-weight exercises such as push-ups, squats and sit-ups, then finish it off with a stretch," she said, adding that dancing "is a great cardio workout."

Whatever she's doing, it's working!