She was left heartbroken after their split 18 months ago.
But Michelle Williams seems set to rekindle her romance with film director Spike Jonze.
Spike, 41, invited the Oscar-winning actress to a gig in New York earlier this month in a bid to win her back.
But the 30-year-old declined, wanting instead to take things slowly.
"Spike realises he made a huge mistake leaving Michelle and he desperately wants her back," says a source.
"They are making a tentative go of their relationship again but Michelle is nervous.
"Spike broke her heart the first time around. He's promised that he's a changed man who is ready for commitment, but Michelle has told him to prove himself before she can trust him again."
Photo: © Rex