Mason and Penelope Disick clearly know how to have fun.
In an adorable video their dad, Scott Disick, shared on Instagram Sunday night, the two tykes can be seen rocking out to Demi Lovato's infectious new song, "Cool for the Summer," in his car.
"Best thing ever," Disick wrote alongside the cute clip of Mason, 5, and Penelope, 3, jumping and swaying to the music.
Missing in action was the family's latest addition, 7-month-old baby Reign.
For more fun photos of Penelope, check out the pictures mom Kourtney Kardashian shared of her 3rd-birthday celebration at Disneyland.