Kylie, 21, and Stassie, 22, have actually been friends for longer than the LipKit mogul and former best friend Jordyn. They met during Kylie's appearance at a Barnes & Noble book store when they were 13 and have been close ever since.
Kylie revealed on her Instagram stories that they were so close growing up that the Stassie basically moved into the Kardashian family home during their high school years.
Khloe Kardashian enlisted Stassie to be one of the models in the "good squad" for her Good American clothing line.
The ladies started suspiciously resembling each other in recent years, and Stassie has been very open about her various plastic surgery procedures, including a breast augmentation. The Kardashian family cosmetic surgeon Dr. Simon Ourian also follows Stassie on Instagram.
As if their bond wasn't already cemented, they got matching "Stormi" tattoos in honor of Kylie's daughter at Travis Scott's birthday party in May 2019.
What are your thoughts on Kylie and Stassie's unbreakable bond? Sound off in the comments.