Michelle Williams is "sad" as often as she is happy.

The 31-year-old actress - whose former partner, actor Heath Ledger, died from an accidental overdose of prescription drugs in January 2008, a few months after their break-up - admitted she has had good days and bad days in her life but she has "no choice" but to stay positive for the sake of her six-year-old daughter Matilda.

She said: "I feel like everybody gets a mixed bag. There's great stuff and there's horrible stuff. It's just that a lot of people know what's in my bag.

"And I can't say that I'm not sad, I can't say that those things aren't true and people aren't making those correct correlations to events and actuality, but I try - because I have no choice, because I have a child - to make something out of it. To make something out of us. To literally remake it.

"Yes, I am sad. I'm sad as often as I'm happy. And so is everybody that I know."

While Michelle accepts that her past is integral to what has made her the person she is now, there are days when she "wilfully" chooses not to let the tragic events get to her.

She added to Britain's Elle magazine: "I went to see this guru and I got to the beginning of the line and she said, 'Your past is behind you,' and it was a huge revelation. It's behind me. It's not all around me any more. It's not all I can see any more.

"And I have to put it behind me even though I don't want to. And some days I wilfully choose not to, but I have to put it behind me if I want to move forward."