The Blue Valentine actress wanted to be a boxer when she was young and dreamed of putting on the gloves and taking on the former heavyweight champion of the world.
Michelle, 30, said: 'First I wanted to be a boxer. I don't know why but I wanted to fight Mike Tyson. That was the dream.'
Although, Michelle soon realised her ambition wasn't going to happen and turned to acting instead.
At just 15, she emancipated herself from her parents after they disapproved of her career choice and she moved away from Solana Beach, California, to star in Dawson's Creek.
Williams added to Stylist magazine: 'I started doing plays when I was eight. I always wanted to act. At 16, I moved away to Los Angeles. [Emancipation] is basically like divorcing them. You have to prove that you are emotionally and financially stable and independent. You have to have graduated high school and you have to prove that you can live alone.
'I did one commercial at first every six months and that was enough.'