Kylie Jenner is Team Khloe in the family's latest scandal, as news of her BFF Jordyn Woods hooking up with Khlo's baby daddy Tristan Thompson last weekend seems to have broken the ladies' longtime bond.

Woods has lived with Kylie for years, as the 21-year-olds were not only best friends but business partners and Jordyn functioned as a kind of personal assistant to Khloe as well. Well that's all over now! Us Weekly reports Jordyn has packed up and moved out of the makeup mogul's mansion.

Eyewitnesses say Tristan and Jordyn were "all over each other" as a party at the baller's house over the weekend after hanging out at SHOREbar in Santa Monica. But even though Jordyn -- who was a friend to ALL the Kardashians and fully integrated into the clan -- seems to have done the ultimate betrayal, Kylie's not sure how to proceed: "At this point, the Kardashians aren’t 100 percent sure if Jordyn is going to be cut out of Kylie’s life. But they’re all looking at it as if she better be," a source tells Us. "It will be very hard for Kylie to lose Jordyn because she’s her best friend. She doesn’t have a lot of friends, and honestly, can’t because of her lifestyle, so she has latched onto Jordyn."

The Kardashians ARE known for their incredible ability to forgive and forget -- they did it with Lamar Odom; they've done it with Scott Disick, with Blac Chyna, etc., etc. So will this recent scandal break apart Kylie's most important friendship or will Khloe allow her half-sister to forgive?