Heath Ledger's daughter Matilda has celebrated her birthday for the first time without her Australian actor dad, who died from an accidental drug overdose in January.

The blonde-haired tot turned three this week with a low-key party believed to have been attended by her mother Michelle Williams and a small group of family and friends at their four-story home in Brooklyn.

Williams has kept their daughter out of the spotlight since Ledger's death, with only rare paparazzi sightings of the mother and daughter in New York parks or at cafes near their home.

Williams is reportedly now dating film director Spike Jonze.

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