Mila Kunis Calls Ashton Kutcher's Proposal the 'Best Day of My Life'

Marie Claire

The usually private Mila Kunis gets particularly candid with Marie Claire for the magazine's July cover issue, in which she spills details about her relationship with fiancé Ashton Kutcher as well as gets into some very graphic birthing details.

Mila and Ashton were famously co-stars on That '70s show when she was just 14 years old, and she tells the magazine that the change in their relationship was actually sudden.

Video: First ET Interview -- 'That' Mila Kunis!

"One day, it just changed. All of a sudden, it wasn't the same. And I was really proud of myself for acknowledging that," she says about their friendship turning romantic.

In fact, she was "a mess" when Ashton, 36, popped the question in February.

"The best day of my life so far was the proposal. I cried. I was a mess," she says. "Not to discredit any relationships in my past, but this relationship is different."

As for how pregnancy has changed Mila, 30, she reveals her breasts have "tripled in size."

"They're amazing! They've tripled in size. I was a 34A; now I'm a 36C," she surprisingly shares. "I'm so excited! I'm telling everyone I know, 'Go ahead, touch them! Without being an a**hole, I have to say, I love being pregnant."

Mila also isn't afraid to veer into TMI territory when it comes to describing how she plans to give labor.

"Two people are allowed in my delivery room. My doctor and my significant other. And he is staying above the action. He'll be head to head. Not head to vag. Unless he wants to risk his life and see," she says. "But I wouldn't if I were him. I highly doubt he wants to see that being ripped apart and shredded. Because it will be shredded. It's just a matter of how badly."

Video: Mila Kunis on 'Fighting for Her Child'

Marie Claire's July issue hits newsstands June 24th.