Their new book, "Kardashian Konfidential," is a fun and breezy read that traces their childhood and offers lots of beauty and style tips. It's also teeming with photos and letters that the girls penned to each other through the years.
And although the sisters smile together for campaigns including K-Dash for QVC, PerfectSkin Products and tanning gel, they still bicker like normal siblings do.
The trio spoke to our friends over at PopEater in the middle of a hectic New York City book tour and one of the topics of conversation was Kim's famous assets. Kim dishes that her older sister Kourtney used to torture her and tease her because she had big boobs.
She adds, "I was 11 when I got my period and I started developing. I would sit in the bathtub, take a washcloth, put it under really hot water and put it against my boobs and pray to God, please don't make my boobs grow any bigger. And Kourtney would be like, "Your boobs are so big and ugly!" She was so mean and then I would have to wear a bra and she would say, "Who wears a bra? That's so disgusting." It was so embarrassing."
The middle sister has found herself defending her curvacious bod in the past. In May, Kim took to her blog to justify her fashion choice after wearing a pair of "mom jeans" that others found unflattering - she wrote, "Any woman who is proud of her curves should be able to flaunt them in high-waisted jeans!!!"
Want further proof that Kim has put the past behind her? She even posed nude on the cover of W Magazine and went au naturel in the pages of Harper's Bazaar!
Check out the rest of the interview for more quips including promotions the girls have turned down and additions to their growning family!
Get more on Kim Kardashian at PopEater