The former Dawson’s Creek star hooked up with the late actor on the set of the movie in 2004, and the pair welcomed daughter Matilda in 2005.
Despite having split up with Ledger before his death from an accidental prescription drug overdose in 2008, Williams said she will make sure their child gets to see the movie when she is old enough.
She told Angeleno Magazine: 'I was just an actor who happened to be lucky enough to be in the right place, and it was the place where I met Matilda's father, and that is a lot. It was a lot. And it will be a lot for Matilda too, when she gets around to watching it. I will watch it with her, when she's ready. It is hard to imagine what that would feel like, but one day, yes, we will watch it together.'