Mila Kunis attends The Screening Of “The Spy Who Dumped Me” at Hearst Tower on July 12, 2018 in New York City.

On the promotional route for her new film, The Spy Who Dumped Me, Mila Kunis has opened up about her relationship with former boyfriend and Home Alone star Macauley Culkin. But it’s her remorseful tone that has people wondering, ‘what did she do to him?’

In a new interview with Dax Shepard for his podcast Armchair Expert, Kunis admits she was reason the pair – who dated for nine years – experienced a “horrible, horrible break-up”. “I f**ked up. I was an a**hole in my 20s and I’ll be the first to admit it,” Kunis said. “And that’s something that took me a long time to come out and be like, ‘Yeah, you know what, I was a d**k,’ and accept it and I own it.”

“And it’s f***ed up what I did,” she continued. “It’s f***ed up what I did, and it’s f***ed up how I did it. When I got to be single I said, I just need to figure myself out. I genuinely need to know why I did what I did and, like, regroup myself as a human being.”

While she didn’t go into what exactly she did – fans have presumed she may have cheated – Kunis says it kind of got to a point where mutual friends began to forgive her for what went down “At 35, I could look back and be like, ‘I was 20.’”

Culkin – who was famous by the age of 10 and a millionaire by 12 –spiraled down the drug path after his break-up with Kunis.

Kunis also recalled how concerned her own mother was when she got together with Ashton Kutcher. He was, after all, fresh from a divorce from Demi Moore. “He was post, post, post, way post-divorce, but I think there was a lot of misconceptions about the divorce,” she said. “People had a weird perception of who he was based on rumours that he didn’t correct.”

“We went into this relationship super transparent with one another, so we knew 100 per cent each other’s faults, we knew exactly who we were. … And we were like, ‘I accept you for who you are.’”