Mila Kunis explains why Ashton can’t be down <i>there</i> during birth

Now that Mila Kunis has confirmed her pregnancy, the actress is willing to talk about it ... in detail.

One perk to be with child? Increased bra size. The actress Kunis enthusiastically called her burgeoning bosom “amazing” during an interview with Marie Claire.

“They’ve tripled in size. I was a 34A; now I’m a 36C,” the “Jupiter Ascending” star told the mag, whose July issue she covers. “I’m so excited! I’m telling everyone I know, ‘Go ahead, touch them! ... I have to say, I love being pregnant.”

This coming from the woman who’s topped on a slew of “sexiest” or “hottest” lists. Careful what you wish for...

The “Family Guy” voice also told Ellen DeGeneres in May that she wants the birth to be as an au naturel as possible. Now she’s got more to say when little Mila or Ashton comes into the world. (P.S. They know the baby’s gender and name but have decided to keep that part private.)

“Two people are allowed in my delivery room,” the 30-year-old said. “My doctor and my significant other. And he is staying above the action. He’ll be head to head. ... . Unless he wants to risk his life and see. 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.”

Tells us how you really feel, Mila.

“He,” of course, is “That ‘70s Show” costar Ashton Kutcher, whom she’s now engaged to after years of friendship. News broke in February that Kutcher popped the question, and the couple were able to keep it a secret for two months before it made headlines. And Kunis provided a little detail to Marie Claire about her reaction.

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

Soon after the engagement news came out, stories that she was pregnant were quick to follow.

The actress said that she had been “really good at saying no” but decided to say yes to any opportunity that arose “no matter how crazy. And it changed my life.”

As for starting a family with Kutcher, the sassy brunet said she just doesn’t want her kids to be arrogant, although she used a much harsher word.

“I feel like so many kids nowadays are. Both of us just want to have well-behaved, honest, nice children who people meet and say, ‘That’s a good kid,’ ” she said.

The full story hits newsstands on June 24.

On Monday, the actress stepped out in a little black dress to join director Paul Haggis and her “Third Person” costars during the film’s premiere at the Pickford Center for Motion Study. On Tuesday, she urged men to stop using the phrase “we’re pregnant” in a faux tirade on “Jimmy Kimmel Live!”

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