The starlet is currently promoting her new film, Bad Mums.
During the press junket for the comedy, the 32-year-old mum candidly spoke about what it was like being a parent to her and Ashton Kutcher's 19-month old daughter, Wyatt.
"I reprioritised my life, in all honesty. I traveled through all my twenties 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," Mila explained to Entertainment Tonight.
Check out her chat in the video player below. Post continues!
"It does change the way you think and look at life. I would never trade it for the world," Ashton's wife continued.
"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."
She may be selfless, but Mila also admitted staying up is now a thing of the past!
"I can let loose as much as I want, but at 6:45 in the morning she's awake, so so am I. They don't care that I let loose the night before. Honestly, I don't know what letting loose means, probably not going to sleep at 9:30," she laughed.
Adding, "[With parenthood] you learn how to be a great partner and great wife and a great woman and be yourself and still be responsible for you know, a living child. It's definitely a learning process."
Mila and Ashton, 38, first met back in 1998 during their time on the beloved sitcom, That '70s Show.
The duo stayed friends before becoming one of Hollywood's hottest items in 2012.
Two years later they welcomed their first child, little Wyatt, before tying the knot the following year.
Watch Mila joke about her partying day being well and truly over. Post continues below!
In 2013, Mila admitted during an interview with Playboy that her family would always be her first priority.
"I want to be a present mum!"
"If that means I do one movie a year, if people still want to see me and hire me and I don't suck by that point, great. But my only source of happiness can't be dependent on something so fickle. And I find this industry to be incredibly fickle."