The model and the former One Direction singer originally sparked speculation when they were photographed leaving a party together after the American Music Awards on Sunday, and now they've been spotted out and about yet again.
An eyewitness exclusively tells E! News the duo enjoyed dinner together at The Nice Guy in Los Angeles on Tuesday night with Gigi's sister, Bella Hadid, and simply couldn't get enough of one another.
"Gigi and Zayn couldn't keep their hands off each other," the source reveals. "They were holding hands under the table, whispering in each others' ears, and Zayn [was] holding Gigi's leg. Gigi was so attached to him that she even followed Zayn outside to the patio during a smoke break."