When Kourtney tried out the filter, Kim remarked how similar the eldest Kardashian looked to Kim and husband Kanye West's 5-year-old daughter, North. Kim and Kanye also share Saint, 3, Chicago, 1, and newborn Psalm.
Meanwhile Kim herself marveled at looking just like daughter Chicago. "I literally look like Chicago," she gushed, before putting on a childlike voice to address Kourtney as the tot. "Auntie Koko, I love my mommy. She's the best."
Scott, Kourtney's ex with whom she shares three kids, also took his turn and appeared to be his 9-year-old son, Mason's, doppelganger. The former couple also share Reign, 4, and Penelope, 6.
The Snapchat fun comes just weeks after Kim and Kanye welcomed their fourth child, a son named Psalm. The newborn's grandmother, Kris Jenner, couldn't help but gush about the newest member of the family while speaking with ET.
"The inspiration [for his name] was the Book of Psalms in the Bible," she shared. "I think it’s just a wonderful way to celebrate how they feel. And he’s such a blessing, so it's perfect."
As for what the cutest thing baby Psalm has done so far, Jenner said, "I don't know, he's just adorable!"
Watch the video below to keep up with the Kardashians.