The pair held hands, kissed and fed one another food as they shared tender moments, putting on a very public display of affection, reported Daily Mail.
The duo, who initially became friends over a decade ago after starring on 'That '70s Show', were first linked romantically back in April - shortly after the breakdown of Kutcher's marriage to Demi Moore.
Kunis had also just come out of an eight-year romance with "Home Alone" child star Macaulay Culkin.
The actress initially denied reports she had jumped into a relationship with Kutcher.
"Listen, Ashton and I hang out. We've known each other for 15 years. We have mutual friends. We're comfortable with one another. That's it! There's no crazy love story, nothing more," she had said.