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Justin Verlander, Kate Upton

James Devaney/WireImage

It's a good time to be Kate Upton!

The recently engaged model-actress celebrated her upcoming 24th birthday Wednesday night with a party hosted by Carine Roitfeld at The Blond Lounge in New York City. Kate's friends and fiancé Justin Verlander all appeared to be having a great time, too, as the B-Day babe quite literally "Partied [her] pants off."

Kate Instagrammed a shot of herself and Justin taken from behind. She's wearing a black thong bodysuit beneath her sheer, starry dress, and while it's no birthday suit in the traditional sense, it's most certainly a cheeky ensemble. If you look closely at the picture (posted by Kate herself) you can see there appears to be a tiny tear in the back of the dress, hence the clever "Partied my pants off" photo caption.

Kate Upton, Justin Verlander, Engaged

Jackson Lee/Splash

An insider at the fete confirmed to E! News that Kate "had a ball," saying, "It was a really fun party. Justin was doting on her the whole time. She looked amazing."

The birthday girl "was dancing on the bar," added an eyewitness. "At one point she was behind the bar pouring people shots because the bartender wasn't moving fast enough for her. It was funny. There was a photo booth and lots of hip hop music playing."

According to an insider, the celebrations continued well into the night and into the next morning past 4 a.m.

Now that's how you turn 24, right? Happy birthday, Kate!

 —Reporting by Beth Sobol