Now that two-year-old Matilda is left to grow up without her doting father, the responsibility to keep Heath Ledger's memory alive falls partly on her famous godfather, Jake Gyllenhaal.
Gyllenhaal, Ledger and Williams, bonded on the set of their Academy Award-winning hit Brokeback Mountain, for which they all received Oscar nominations.
"Heath and I are best friends now making the film was very intense for us," said Jake, 27, who played Heath's sheep-herding love interest in the blockbuster hit. He described being Matilda's godfather as "an amazing honor."
"I remember being in rehearsal, and the two of them had googly eyes with each other," he has said of the romance between Matilda's parents.
There are already concerns about how Matilda, at such a young age, will be affected by the passing of her father.
Heath Ledger lavished gifts on his only child. He regularly brought Matilda to the high-end SoHo store Calypso Kids where he spoiled the little tyke, buying her life-size stuffed animals and anything she wanted, especially ice cream, a saleswoman told the New York Post.
Despite her unimaginable loss, Matilda should expect to have an extended family in the Gyllenhaals.
Jake's sister, Maggie, befriended Ledger during the filming of their upcoming Batman sequel The Dark Knight. Maggie, 30, and Peter Saarsgard, whose daughter, Ramona, is one year younger than Matilda, also own a Brooklyn brownstone nine blocks away - a mere five minutes on foot from the Hoyt Street townhouse Ledger and Williams formerly shared.
While information about Ledger's will is still unclear, Matilda stands to inherit millions. He was paid well over $3 million per role.