The 32-year-old, who had kept the memory of her former fiance, the late Heath Ledger, alive by staying in the house they shared with their beloved daughter, has left the Brooklyn brownstone she bought with him.
Williams and Segel have moved into a sprawling loft overlooking the Manhattan skyline, reported Daily Mail.
"Michelle, Jason and Matilda seem very happy here, the building is beautiful. They've been here a few months now and they look right at home," a source said.
The couple have been friends for a long time and started dating earlier this year.