Jason Segel and Michelle Williams have taken their relationship to the next level after reportedly moving in together in New York.

The fiercely-private couple was first photographed together in March after enjoying a dinner date near the Brokeback Mountain beauty's home in Brooklyn, and the stars went public with their romance a month later at the Big Apple after party for Segel's romantic comedy The Five-Year Engagement.

Now, the romance appears to be getting serious after Williams decided to leave the pad she and her daughter, Matilda, once shared with her tragic ex-fiancé Heath Ledger and move in with Segel.

According to the DailyMail.co.uk, the pair has set up home in a sprawling Brooklyn loft apartment, located in a converted warehouse, with stunning views of the Manhattan skyline.

A source tells the publication, "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."

Matilda, who turns seven on Sunday, is Williams' only child with Ledger.

Williams split from Ledger in 2007, shortly before he died from an accidental drug overdose in January, 2008. She went on to date filmmakers Spike Jonze and Cary Fukunaga before finding love with Segel.