In a Snapchat video shared by fellow partygoer Jen Meyer, the "Shake It Off" hitmaker was seen kissing Mike on the cheek before they danced closely together.
Mike, who also celebrated his birthday that night, then slightly wrapped his arm around her waist, reported Ace Showbiz.
Mike is a friend of Karlie's boyfriend Josh Kushner. His parents own the Hess Corporation.
According to the insider, Taylor and Mike didn't hang out too much except for a little dancing.