The Keeping up with the Kardashians star and Lakers player were captured on Snapchat over the weekend getting silly together, and a source tells PEOPLE the duo are getting more serious.
"They keep things low-key when they're in public, but in private they're very much together and affectionate," says the source. "He's really into her."
According to the insider, Jenner hung out with her pals her first night in Coachella but stayed with Clarkson the rest of the weekend.
As for rumors she's rekindling a romance with Harry Styles? "If she was talking to Harry, she would not have been in Palm Springs with Jordan," says the source.
The budding couple first met last fall and "have been secretly dating for months," another insider said last month. "He is super sweet and a total gentleman and Kendall loves that."