Mila Kunis stuck to Ashton Kutcher's side when the couple attended a concert during the Taste of Chicago event in the Windy City yesterday. The pair stood offstage while Robin Thicke and Estelle performed for a large crowd of fans. Ashton met up with Mila after taking a trip to Paris to screen his latest film, Jobs, based on the life of Apple founder Steve Jobs. Their cuddly appearance at the Robin Thicke show comes a few weeks after their friend and That '70s Show costar Laura Prepon hinted that wedding bells could be in the couple's future. She said, "They are totally going to marry, we just don't know when." Laura also added that she would likely be a bridesmaid at the event and that her costar Wilmer Valderrama would be involved in the wedding party in some way. While neither Ashton nor Mila have announced any official plans to get hitched anytime soon, they have been spending quite a bit of time together. Ashton joined Mila in London while she was filming Jupiter Ascending in May, and the couple popped up in the South of France in June for a yacht date with Princess Beatrice and her boyfriend, Dave Clark.