"I don't think you will be seeing them make a public announcement anytime soon, but there is something going on there for sure," the source added. "It's been going on for a while. Kendall is happy."
Jenner and Rocky, 28, were recently spotted together at fashion's biggest night, the Met Gala in New York City on Monday. Though they didn't walk the red carpet together, they had no problem packing on the PDA inside the party.
In a photo posted to sister Kim Kardashian West's Snapchat, you can see Rocky grabbing Jenner's booty, which was on full display in her sheer La Perla gown and embellished black thong. Her youngest sister, Kylie Jenner, sneaked in a snapshot of the flirty moment, too!