Michelle Williams is "not over" Heath Ledger's tragic death.

The actress is said to be still grieving four years after the Hollywood star passed away following an accidental prescription drug overdose.

According to sources, the My Week with Marilyn beauty hasn't moved on after losing her "soulmate". She is believed to have struggled to celebrate her Golden Globe win as it coincided with the fourth anniversary of Heath's untimely death.

"Michelle still loves Heath, and there isn't a day that goes by that she doesn't think of him. She's not over it," an insider told OK! magazine.

The pair had met on the set of Brokeback Mountain in 2004.

In 2005, their daughter Matilda was born but Michelle and Heath separated two years later despite being engaged.

Heath was only 28-years-old when he was found dead in his hotel room in January 2008.

"Michelle and Heath hit a rough spot, and they decided to take some time apart," the source added. "It was really sad because they still loved each other and Matilda."