Port, 30, who was celebrating with friends at the city's Omnia Nightclub, posed for a photo with her former castmate Jenner, 31, and Devin Lucien. Jenner and Lucien DJed a set at the Caesars Palace club on Saturday.
The reality starlet, who's set to wed Tim Rosenman, marked the end of her single life with a bevy of beauties at the famed hotel.
"Whitney couldn't stop smiling dancing around to music while getting ready for the night out at Omnia Nightclub," a source told PEOPLE.
Before making their way out for the night, the ladies and bride-to-be got their hair and makeup done by celebrity stylists from the new beauty app beGlammed.
Port documented her evening on Instagram, and wore a white dress to stand out as the bride among her friends, who were clad in black.
"Ok! Ready," she wrote along with a picture of her crew.
In another photo, Port applied deep red lipstick in front of a mirror.
"Yesssssssssss," she wrote.
The girls also posed for a group photo at Omnia.
"Let's get this party started," Port wrote.
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Port met Rosenman through her The Hills spinoff series, The City, where he served as an associate producer. The couple began dating in 2012 before getting engaged in 2013.
Reporting by PATRICK GOMEZ