The Jobs star, 36, was photographed getting handsy with his pregnant fiancée, 30, in Los Angeles on Sunday, May 18. Click here to see more pics of Mila.
Looking casual in a pair of light-wash jeans, a plaid button-down shirt, Nike sneakers, and a backwards baseball cap, Kutcher was seen grabbing Kunis' butt as they walked to their car.
Earlier in the evening, the lovebirds reportedly attended a wine tasting party with their good friends.
Kunis, who wore a flowing printed maxi skirt and two layered tank tops, got behind the wheel to drive the couple home after the affair.
In preparation for their first child together, the happy couple recently purchased a gorgeous new mansion in Beverly Hills for a reported $12 million. A source told Us the home is "perfect for a family" and offers "lots of privacy," in addition to a pool, vegetable garden, three bedrooms, and four bathrooms.
Though Kunis and Kutcher first met on the set of their late '90s sitcom That '70s Show, they didn't begin dating until 2012, when they both became single following Kutcher's split from Demi Moore and Kunis' breakup from Macaulay Culkin. The actors quickly fell in love and are planning to wed in 2015 after the birth of their child later this year.