Kunis, 31, wore a pair of loose black pants and a simple top covered by a tailored black jacket.
Fiance Kutcher, 37, was similarly dressed down in baggy blue pants and a Vision Street Wear sweatshirt, topping off his outfit with a red baseball cap.
Dining at Hal's Bar & Grill in Venice, California, with some friends, the stars were just few distance away from Kutcher's ex-wife Demi Moore, who was talking to friends with daughter Tallulah Willis outside bar Roosterfish.
He began dating Kunis in April 2012, and they got engaged less than two years later, in February 2014. They welcomed their first child last October.