Article continues below advertisementCould Nina Dobrev and Zac Efron be Hollywood's next dream pair? The A-list stars were spotted spending time together during a European vacation with friends just one week after a source confirmed Dobrev and her ex-fiancé, Shaun White, had called off their engagement.Dobrev and Efron made headlines after their mutual friend Keleigh Teller shared photos of the group enjoying a yacht day off the coast of Italy via Instagram on Thursday, September 18.