Kardashian, who went braless and wore a floor-length dress with a thigh-high slit for the bash, posed with her on-again, off-again boyfriend for some photos. And at one point during the fete, Kardashian and the birthday boy - who broke up in September and are recently rumored to have reconciled - sat close to one another on a couch. See the pic here.
"Khloe and French are clearly together - they were hugging, holding hands, and being openly affectionate," a source told Us Weekly.
"They were... hugging and very much a couple," another eyewitness told People.
Kardashian also played hostess at the party. She was "running around and talking to [a party planner]" throughout the night, an insider told Us Weekly.
"[She was] making sure everything was running smoothly," a source told People
Montana's close friends Sean "Diddy" Combs and Snoop Dogg were also part of the celebration. Other guests included Hadid's family friend and fellow Bravo star Lisa Vanderpump, Gretchen Rossi, Evan Ross and Ashlee Simpson.
The entire E! camera crew was also in attendance, as "French's party was filmed for the show," another source told Us Weekly.
Earlier that day, Kardashian posted a sweet birthday greeting for Montana, fuelling rumors that the two are back together.
"Happy birthday baby boy! In only a short amount of time we have created timeless memories. Happy birthday to a man who genuinely lives life to its fullest," the 30-year-old "Kourtney & Khloe Take the Hamptons" star captioned a romantic beach photo of them two.
"What's understood doesn't need to be explained," she added. "@frenchmontana I can't wait to celebrate life with you tonight! You deserve it!!"
Montana appeared on "The Wendy Williams Show" on Oct. 31, and while he did not reveal whether he and the 30-year-old reality TV star are back as boyfriend and girlfriend, he did imply that they might have reconciled.
"You know like every relationship, you break up, you make up. Right now we're on real good terms," Montana told Wendy Williams, as quoted by New York Daily News.
"We're in a real special zone right now," Montana added. "She's gonna be my baby forever."
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