North West & Penelope Disick Support Their Naked Aunt Khloe Kardashian

There's nothing sweeter than little kids who love their family -- even when said family member is posing nude on the cover of a book the kids aren't even old enough to read.
"I can't stop smiling when I look at this photo! I love my little ladies!" Khloe captioned the cute snapshot. "They were so excited and kept screaming 'KoKo!' 'KoKo!' North calls me 'KoKo Loco.'"

It's hard to pinpoint what aspect of this photo is the cutest: 3-year-old Penelope and 2-year-old North's carefree smiles, or that, as little kids, they look like they don't quite understand how to hold a book.
The 31-year-old Keeping Up With the Kardashians star has been busy promoting her best-selling book, but recently had to cancel a stop on her publicity tour after coming down with a "minor infection," a source recently told ET.
Check out the video below for a look at some of the candid revelations Khloe shares in her new memoir.