According to People magazine, the stars tied the knot this weekend, reps have not yet responded to requests for comment.
There were several rumours they had been married earlier this year but they are finally married now.
Kutcher, 37, and Kunis, 31, met while playing love interests on the Fox sitcom, which ran from 1998 to 2006.
“My first real kiss ever was with him on the show,” she said in W magazine’s August issue, adding, “We all get movie star crushes. I’m marrying mine.”
Mila and Ashton had a baby girl in October 2014 and they’ve tried to keep everything about their relationship and child ‘hush hush’.
Ashton used to be married to Bruce Willis’ ex wife, Demi Moore.