The only person more excited for Jennifer Lopez's 47th birthday than herself was probably Kim Kardashian

The E! reality star jetted off to Las Vegas over the weekend for a girls' trip, and as fate would have it, she had the lucky opportunity to present the birthday girl with a massive cake. An inside source tells E! News the impromptu party took place after Jennifer's sold-out "Jennifer Lopez: All I Have" residency show at Planet Hollywood, which Kardashian attended alongside multiple girlfriends and rapper French Montana

In videos shared by Kardashian on her Snapchat, the duo shares a warm embrace before the entire crew breaks out singing "Happy Birthday" in honor of the chart-topping songstress. Lopez also manages to steal a quick smooch from beau Casper Smart as she blows out the candles. 

French Montana, Kim Kardashian, Jennifer Lopez, Calvin Harris

Instagram

Calvin Harris was also present for the celebration, and the foursome posed for a photo op together later shared by Khloe Kardashian's ex on his Instagram.

Other stars present for Jennifer's concert included Iggy Azalea, Cristiano Ronaldo, L.A. Reid and John Stamos, the source adds. Kim documented much of the performance on her Snapchat, sharing videos of Lopez absolutely killing it onstage as well as her lip-syncing along to her hit songs. 

Speaking of lip-syncing, did we mention Kim couldn't help but bust out her own rendition of husband Kanye West's controversial song, "Famous" while partying at a Sin City nightclub on Friday?

Kim Kardashian, Jennifer Lopez, Instagram

Instagram

And if you're confused by Kim and J.Lo's seemingly unlikely friendship, think again. The 35-year-old has never been shy when it comes to fangirling over Lopez, referring to the pop sensation as her "idol" on more than one occasion. 

At the Met Gala in 2015, Kardashian shared a photo of the duo walking arm-in-arm with the caption, "With my idol @jlo." Just a few months later, while Kim was pregnant with second child Saint West, she gushed on Twitter, "Damn!!!!! How hot does @jlo look!!!!! She will forever be my idol!!!! #BodyGoals"

A year prior, the social media phenom was spotted out and about with a copy of Jennifer's memoir, True Love, in hand. 

Kim Kardashian, Jennifer Lopez

Seth Browarnik/startraksphoto.com

As for how Lopez feels about the could-be president of her fan club, the 47-year-old told USA Today in May 2015 she totally loves it. 

"Oh, I've met Kim many times. She tells me all the time that I'm her idol and stories about when she used to follow me when my first album was out, and stuff like that," Lopez dished.

"It's really sweet. She's a sweet girl, and it's very flattering to meet any of your fans! She's always been very open about that and it's very flattering to me. She's a sweetheart," she added.

—Reporting by Holly Passalaqua 

Watch a new episode of Keeping Up With the Kardashians Sunday, July 31, at 9 p.m. on E!

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