This is 46?!

Jennifer Lopez didn't look like she had aged a day when she stepped onto the red carpet at club 1OAK in Southhampton, New York.

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The "Booty" singer showed hers off in an LBD that was more little than dress -- the skintight number featured a low neckline, numerous cut-outs and sheer panels.

Let's be real -- the frock was more bits of fabric than a full dress, but Lopez clearly pulled it off. She completed the look with strappy sandals, silver accessories and white nails.

The mom-of-two walked into the party hand-in-hand with boyfriend Casper Smart, who was dressed smartly in a baby blue suit jacket, white button-down and navy pants.

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Even Kim Kardashian couldn't help but point out how good her J.Lo looked, tweeting about her #bodygoals.

J.Lo definitely enjoyed her party, dancing and even getting behind the DJ booth at one point. Meanwhile, guests sipped summer-inspired cocktails by Ciroc Vodka and fought to snap their own selfie with the diva.

Earlier in the afternoon, the couple celebrated Lopez's big day with her kids -- 6-year-old twins Max and Emme with her ex-husband Marc Anthony -- on a boat in the Hamptons.

Lopez and Casper originally called it quits in June 2014 before rekindling their romance a few months later, kicking off this past New Year's together in Las Vegas.

The actress-singer-entrepreneur's actual birthday was on Friday, which she celebrated with a cheeky Instagram post of Marilyn Monroe.

Find out what Lopez had to say about Casper's boyfriend skills in the video below.

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