The famous siblings from the popular reality show are known for their closeness, but this time they competed with each other and engaged in friendly rivalry as they joined opposing kickball teams for Chris Brown and Quincy's Kick'n It For Charity event in Glendale last Saturday.

The 18-year-old model played on the R&B singer's team while her 16-year-old sister played for Diddy's stepson, Quincy's team. All proceeds from the game would go to Symphonic Love and Best Buddies.

And they wore very interesting footwear, too. In one of Kendall's many Instagram photos highlighting the event, she posted a snap with her sister as they stood with their backs in front of the camera, with Kylie wearing thigh-high heeled boots and her sister wearing cut out Balenciaga combat boots.

But even more interesting was the fact that they were seen getting cozy with big sister Kim Kardashian's ex-friend, Paris Hilton. Kendall was in the same team as the hotel heiress, and at one point, Kendall was even standing beside Paris and laughing together.

Back in 2008, the Kardashian-Hilton feud started after the Stars Are Blind singer mocked Kim's infamous backside in a radio interview, comparing it to "cottage cheese inside a big trash bag."

While Paris apologized formally after the incident, the two BFFs have not been seen together since. Uh-oh! We hope Kanye's wife and North's baby momma isn't too angry with her little sisters!