Hollywood couple Heath Ledger and Michelle Williams have reportedly called time on their three-year relationship.

Reports stateside from US Weekly and People magazine claimed that the pair, who met on the set of Brokeback Mountain in 2004, had decided to part ways after a "Rocky period".

But a source said they "did all they could to make it work" before splitting up in August.

Williams, whose breakthrough role came in TV's Dawson's Creek, admitted earlier that caring for the couple's two-year-old daughter Matilda had initially placed strain on her professional commitments.

"We started promoting [Brokeback Mountain] about three weeks after Matilda was born, which was too soon.

"I'm learning lessons now, like learning how to be a working mom."

The couple's co-stars on the Oscar-winning Ang Lee epic said that it was love at first sight for Ledger, 28, and Williams, 26.

"I remember being at rehearsal and seeing the two of them sort of like googly-eyed looking at each other," said Jake Gyllenhaal.

Anne Hathaway added: "There were sparks immediately."

Ledger can next be seen on the big screen in Batman flick The Dark Knight starring as the Joker alongside Christian Bale's caped crusader.

03/09/2007 13:04:11