The actress, who secretly married Ashton Kutcher last year, lets loose in the new trailer for Bad Moms.
Hitting cinemas in July, the comedy features Mila playing stressed-out mum Amy Mitchell who decides it’s best to loosen up a little.
The teaser begins with Mila trying to juggle tasks such as bake sales and emergency PTA meetings before being pushed to the limit.
She then decides to throw caution to the wind, saying: “I’m so tired of trying to be this perfect mum. I’m done.
“We all work too damn hard trying to make our kids’ lives amazing and magical. Their lives already are amazing and magical.”
Mila – along with partners in crime Kristen Bell and Kathryn Hahn – then toast to being ‘bad mums’ and completely change their ways.
One naughty scene sees Mila strip down to her underwear before having her bra inspected by her pals.
“Is that your mum bra? It looks like one long boob,” she’s told.
Mila then responds: “This is my sexy bra.”
Bad Moms is directed by The Hangover’s Jon Lucas and Scott Moore.
The film also stars Christina Applegate and Jada Pinkett Smith as two alpha mums who are impossible to live up to.
In real life Mila is a proud mum after welcoming daughter Wyatt Elizabeth in October 2014.
Promoting the new comedy, the 32-year-old has confessed that motherhood has helped her become ‘selfless’.
“I travelled through all my 20s and I was very selfish… In a good way, not in a way I regret. And I think having a kid made me realise how incredibly selfless I want to be.”
She added to Entertainment Tonight: “It does change the way you think and look at life. I would never trade it for the world.
“But I know that when we decided to have a kid, we were ready to no longer be selfish. Or at least start the process, because innately, as humans, we are really selfish people.”
*Bad Moms is scheduled to hit cinemas in the US on July 29.