It's hard to believe, but today Knox and Vivienne Jolie-Pitt turn 4 years old!
We love seeing the littlest members of Brangelina's brood traveling around the world. Last year, Angelina Jolie told Marie Claire that Vivienne is a "girlie girl" who "likes to get her nails done and [collect] stuffed animals."
Knox, on the other hand, "is very much a dude," Mama Jolie says. "He loves dinosaurs and swords."
In honor of these two cuties on their birthday, take a look back at their adventures with Angie, Brad Pitt and big sibs Shiloh, Pax, Zahara and Maddox!