Tonkin and Wesley, who confirmed his split from wife Torrey DeVitto in July, were spotted out at Soho house in Manhattan on Saturday on what appeared to be a double date.
"It looked like Paul and Phoebe might have set up Ben and Shelley," said an eyewitness, referring to Tonkin and Wesley's friends, actors Ben McKenzie ("Southland") and Shelley Hennig ("The Secret Circle"). "Seemed like a first date."
"Paul and Phoebe were 100 percent romantic -- they were across the table from Ben all cozied up on the couch kissing each other," the source added. "She had her head on his chest."
Tonkin's new show, "The Originals," as well as "The Vampire Diaries," debut October 3.