The Ted star looked stunning in a pink dress as she served as a bridesmaid for her brother Michael Kunis's wedding in St. Petersburg, Fla. Saturday, with Kutcher on hand for support.
"Mila wore a gold band on her engagement ring finger but it didn't have a diamond, just a simple gold band similar to a wedding band," a source told E! News. "Mila was very happy for her brother and his wife. During the ceremony, she stood at the altar and seemed very focused on the vows."
But while Kunis has been spotted multiple times with that gold band on that finger, at some point before hitting the aisle she moved it to her right hand.
"Every once in a while, [Mila] would look out to Ashton and make eye contact with him," the source continued. "Ashton was very supportive of Mila and happy for the family. He was joking around with Mila's brother and they invited him to come and pose for family pictures with the bride and groom after the wedding."
The source said the couple looked "totally in love and inseparable at the wedding."
"They rarely left each other's sides and were always holding hands and whispering to one another," the source went on. "Ashton let Mila do her thing but always was right there at her side. If she was busy, he knew lots of people to talk to and was having a great time with her parents and friends."
"It was a really happy occasion for the family and a great day for everyone."
The wedding was held at the cathedral church of St. Peter, with guests later attending a reception at the historic St. Petersburg Yacht Club.
For more details on Ashton and Mila's wedding excursion, tune in to E! News Monday at 7 p.m. and 11:30 p.m. only on E!.
-Additional reporting by Michelle Falls