Mila Kunis told us what she did after giving birth. And it's nothing to do with being a mum.

Mila Kunis is no stranger to the world of motherhood.

In addition to welcoming a baby with husband Ashton Kutcher in 2014, she’s currently pregnant with baby number two.

Her latest on-screen venture sees her play a struggling and under-appreciated mum called Amy Mitchell in her new film, Bad Moms.

The film focuses on a group of mothers who cast off the responsibilities of motherhood, reject the quest for perfection and embrace fun and chaos.

It’s the first time Mila has been back on screen in a leading role since giving birth to Wyatt, who turns two in October.

"My character's desire to be perfect, and figure out a way to balance work and life is something that I gravitated towards," she tells Mamamia.

"Having a child and thinking about going back to work, especially in the field that I'm in, where an average day is about 16 hours, was something I definitely related to."

The fact that Mila plays a mother in the film is "very much kismet", the actress tells us.

"The movie, the project, the girls that were in the entire cast, everything about it was very meant to be.

"Being at work around four other women that were going through the exact thing that you were on a daily business, like 'Oh, my kid's got a cold and I didn't sleep at night', made for a much easier shoot."

While the 32-year-old can relate to the desire to be a 'perfect mum', she surprisingly admits that the pressure doesn't come from the media or her hordes of fans.

Instead, she says the pressure comes entirely from "me, myself and I".

"My husband [actor Ashton Kutcher] and I put all the pressure on ourselves," she says.

"It has nothing to do with what other people think, it merely has to do with being able to, hopefully, put out a decent person into this world that adds some positivity and light."

On the cusp of becoming a mother to two young children (her due date is rumoured to be around late Novemnber) Mila offers up some sage - and surprisingly specific - advice for new mothers.

"My first word of advice is to never give advice," she laughs.

"But if you're lucky enough to create a little human with a partner, my word of advice is to create a reservation at a restaurant four weeks after giving birth," she says.

"Create the reservation months [in advance]...so that you and your partner can have a moment to yourselves. It's so easy to lose yourself in your kid, and stop being a wife and stop being a partner, and stop being yourself.

"I think it's important to remember that you should come first, you and your partner should come second, and your baby comes first to the both of you."

Mila admits that putting yourself first is hard, and as a woman we can't help but "constantly feel guilty".

"It's such a weird thing. I don't know why - I don't even think it has to do with being a mum, it's all women - you just have guilt sometimes," she says.

Bad Moms is in Australian cinemas from August 11.

Mila Kunis, Kristen Bell, Ashton Kutcher and Dax Shepard play 'Never Have I Ever'.