The 31-year-old actress opened up about losing her baby weight, citing feeding her baby girl as a workout in itself.
She told Jimmy Kimmel: "Breastfeeding is like working out. That, and it's true I am very active. I hike almost every day with her. I strap her in a papoose, and away we go."
Mila, who is rumoured to have married partner and Wyatt's dad Aston Kutcher, 36, also revealed she got emotional the first time she went out without her baby.
She said: "It's really weird to be out. This is my very first time out and about. I swear to God! I left [Wyatt] at home yesterday for the first time during the premiere [for Jupiter Ascending].
"Its frightening. I have to be honest. I was with her every day for the first four months of her little life. I cried, I did.
"It's weird. It's very strange. If anyone's a mom, and being a stay-at-home mom, it's a very weird feeling to all of a sudden leave your child."
And Mila confessed that Ashton asks her to test out dating apps for his investments. She said: "I'm on [Tinder] going, 'What is this?!' Like, swiping things left and right. I was like, 'This is amazing!'"
"This is the stuff that I do at home. He makes me go on all of these websites.
"What's the gay version of Tinder? Grindr! I've been on Grindr!"