Michelle Williams was suppose to start filming Blue Valentine next month.  Production on the film has been delayed to give Williams time to grieve for Heath Ledger.

Filming on her next movie, Blue Valentine, has been postponed while she takes the time to grieve for Heath Ledger, her onetime fiancé and father of her child, the producers of the film confirmed Tuesday to E! News. 

Production was due to begin Feb. 25 but has been pushed back indefinitely.

Williams and Ledger broke up last August.  The two met and fell in love on the set of Brokeback Mountain.