The pair attended the Republic Records MTV Video Music Awards after-party at Vandal restaurant in New York City on Monday night, where the two engaged in plenty of PDA, an eyewitness tells ET. The two got comfortable at a VIP table, sitting on a loveseat together.
They were "very cozy and kissing each other," the eyewitness says. "They are not hiding their affection for each other at all."
Grande also sat on Miller's lap, giving him a kiss on the lips as he put his arm around her. The two later shared a few dances, with the "Problem" singer dancing on the rapper's lap at one point, the eyewitness notes.
The pair didn't seem to mind people watching, either, partying alongside Jaden Smith, Rita Ora, and singer Travis Mills.
"They [were] letting people take pictures of them cuddling and kissing," the eyewitness says.
The night's festivities included a performance by Desiigner of his hit song, "Panda," and the couple munching on a delicious looking tray of avocado toast.
Grande, 23, and Miller, 24, eventually left the party holding hands. Grande looked comfortable rocking a very '90s ensemble of light-wash denim overalls unclipped on the left side, a white spaghetti strap crop top, and a black choker.
Reports surfaced last week that Grande and Miller were dating after they were spotted getting close on sushi dates and stealing kisses, and later spotted getting inked together at Shamrock Social Club in Los Angeles. But the duo has actually been friends for a while, collaborating on her 2013 song "The Way."