JE1 / Judy Eddy / WENN 1 / 11
JE1 / Judy Eddy / WENN 1 / 11

Major curves ahead!

It's not every day Kim Kardashian's little bro celebrates his quarter-century birthday, so for the special festivities, she made sure to get decked up in a head-turning outfit.

At Rob Kardashian's 25th birthday bash at 1Oak in Las Vegas Friday, Kim slipped into a sexy, asset-hugging white mini dress decorated with patches of silver sequins and cut outs on the shoulders.

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Kim and Rob's mom, Kris Jenner, was also at the fete and donned a chic red dress.

"Happy Birthday Robbie!!!!" Kim, 31, tweeted along with a photo of the three of them via Instagram.

Although Rob's other older sisters weren't in attendance, they still gave shootouts with family pics on their respective personal blogs Saturday.

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"Happy Birthday to the best brother in the world! I CANNOT believe you are 25!!! Truly I can't!," Khloe, 27, wrote. "God blessed me with an amazing brother. Our bond is unbreakable, even though I want to strangle you sometimes, I still adore you!"

"Sending lots of love to my baby brother Rob today on his 25th birthday!!" Kourtney, 32, posted. "Rob, I am so proud of the man you have become. Here's to an amazing 25th birthday… I love you so much!"

PHOTOS: The Kardashian family album

Prior to hitting Rob's luxe bash, the family (sans Khloe and Kourtney) stopped by the Kardashian Khaos store in the Mirage Hotel -- with Rob's leggy half-sisters, Kendall, 16, and Kylie, 14, in tow.