Kendall & Kylie Jenner Hang Out With Nephew Reign Disick & They've Got This Whole Aunt Thing Down — PHOTOS

Back in the earlier seasons of Keeping Up With the Kardashians, Kendall and Kylie Jenner were the babies of the family. They practically grew up right before fans' eyes. Now, there are some other youngins stealing the spotlight. From Kimye's newest addition Saint West to Kourtney Kardashian's three kids, this famous family tree keeps growing. In case you were wondering, Kendall and Kylie take their role as aunts very seriously. On Saturday, the Jenner sisters posed with Kourtney's youngest son Reign. Warning: The photos are so adorable that your heart will instantly melt.

According to People, this was a birthday celebration for two of the Disick kids. Reign turns 1 on Monday, but he also shares a birthday with big brother Mason, who will be 6-years-old. So much to celebrate! Unfortunately, Mason didn't make it into any of the photos, but it was a glamorous shoot nevertheless. Part of me thinks this can't be all that Kourtney is doing to celebrate, considering she was out playing laser tag on Saturday night. Maybe the Jenner girls were just babysitting? Kylie referred to her and Kendall as "cool aunts" and she couldn't be more right.

Lucky for fans, Instagram is basically a virtual photo album for the Kardashian-Jenner fam. Here are all of the adorable highlights from Auntie Kylie and Kendall's hangout with Reign.

Multi-Tasking

Texting and babysitting — Kendall can do both at once. Although, I can't imagine anything on her phone is better than what she's holding in her hands. Just look at that little face!

Penelope's Glamour Shot

Is it normal to envy a toddler's outfit? If so, I need to know where P got that skirt. The sunglasses, too.

Snuggles

Reign's little jean jacket is too cute for words. Sadly he seems unimpressed by all of Kylie's love.

The Coolest

To borrow from that classic Mean Girls quote, they're not regular aunts; they're cool aunts.

My vote is that these two become the Disick kids' official babysitters from now on. They've totally got the whole aunt thing down.

Image: Giphy