No F-ing Way!!!! We never expected this!

We KNOW Tristan Thompson's a dirty cheating pig, but he's been hooking up with Khloe's half-sis Kylie Jenner's BFF Jordyn Woods?! Jordyn's in business with Kylie now -- Kylie so generously giving her "personal assistant" her own spin-off of the Jenner beauty empire and she repays her like THIS?!

Apparently an eye witness reports Woods, 21, "making out" with Tristan, 27, at a house party this past weekend. When Hollywood Unlocked broke the story via Instagram, Khloe herself commented with multiple talking head emojis and her best friends rallied to her side -- Malik Haqq commenting, "STRONG FACTS," and pal Larsa Pippen writing, "Amen!!!!" What do YOU think happened? Is this story for real or is this Kris Jenner drumming up a story to keep the family's reality show going?!