actress was a tomboy when she was growing up who enjoyed playing games with her older brother and his friends and preferred playing outdoors to watching TV.
And it wasn't until a boy made her heart flutter that she embraced her girlie side.
Mila said: "I have an older brother, he's six years older. So when I was growing up, my parents would be like, 'Go play with Mike.'
"I grew up in a small town in Ukraine, where kids went and played out in the neighbourhood all day long. You got kicked out of the house and ran around for eight, nine hours and came back completely scraped up and bloody and starving.
"You didn't play video games or watch TV. There were more boys than girls in the neighbourhood and I idolised my brother, so for sure I was a tomboy.
"I didn't know I was a girl until I started liking boys. Like when I developed a crush on my brother's friend and I was like, 'He's cute.' I think that's when his whole world crumbled, when his little sister was all of a sudden asking, 'Who's that guy?' "
The 28-year-old beauty - who has recently been romantically linked to Ashton Kutcher - admits she never liked dolls and was more interested in her brother's toys.
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She added: "We didn't have toys, you played with other people. I didn't like dolls, you played with little soldiers and you ran around the neighbourhood."