Kim Kardashian Bonds With Beyonce in Atlantic City

After touring Cannes, France last week and unexpectedly parting with some "sentimental" items in her luggage, Kim Kardashian was looking to let loose.

So on Sunday, the "Keeping Up With the Kardashians" star made a beeline for Beyonce's concert at Revel's Ovation Hall in Atlantic City, N.J., for a night of dancing and singing along with the songstress's chart-topping hits.

PHOTOS: Stars in concert

Backstage, Kardashian, 31, got a chance to chat with the woman of the evening herself, and the pair were seen greeting each other with an embrace and dancing together. Beyonce's husband of four years, Jay-Z, is best friends with Kanye West, Kardashian's serious boyfriend.

"Kim thought it was such a great show," a source tells Us Weekly. "There's always some random rumors there is tension between them, and there totally isn't! Kim had so much fun."

PHOTOS: Kim Kardashian's rough year

The E! star is one of several A-listers who made it out to Beyonce's four-concert weekend, which marked her post-baby performance debut since giving birth to daughter Blue Ivy in January.

On Saturday, first lady Michelle Obama, 48, and her daughters Malia, 13, and Sasha, 10, watched the show from a private box where they did the "Single Ladies" dance together and rocked out to "Crazy in Love." Oprah's BFF Gayle King sat nearby.

PHOTOS: The Obama family album

During Saturday's encore, Beyonce, 30, revealed to the sold-out venue that she had lost a whopping 60 pounds since giving birth.

"Y'all have no idea how hard I worked! They had me on that treadmill. I ate lettuce!" she told her fans. "Now tonight I'm gonna get chocolate wasted!"

MORE FROM WONDERWALL:

Michelle Obama's dream job: Being Beyonce

Hollywood's Best-Dressed Moms

Mood Swings, Weight Gain and Cravings: Celebs Talk Pregnancy