Michelle Williams attended a private ceremony Saturday in Los Angeles to honor her ex Heath Ledger, a source tells Usmagazine.com.

The ceremony was held at the Sony Studios.

In addition to his family, Josh Hartnett and Ledger's other ex, Naomi Watts, as well as other industry figures and people connected to CAA (the agency that represented Ledger), attended.

Musician Ben Harper performed. (Ledger had directed Harper's video, "Morning Yearning.")

Australian paper Perth Now is reporting that Ledger's grieving family, including father Kim, mother Sally and elder sister Kate, left L.A. for Australia on Sunday night.

Funeral arrangements remain unknown.