Actor Heath Ledger arrived at the Venice Film Festival alone today as family confirmed he has split from partner Michelle Williams.

The couple are said to have separated after three years together.

Brokeback Mountain star Ledger, 28, looked grim-faced and spoke only briefly during a press conference for his new Bob Dylan film I'm Not There.

Williams, 26, also appears in the movie but did not accompany him to promote it.

The couple got together while filming Brokeback Mountain in 2004 and their daughter Matilda was born in October 2005.

Williams' father, Larry, told Australia's Daily Telegraph: "We have known about their troubles for a while but it's always a very difficult thing in life when these things happen.

"I know Heath and Michelle still care about each other deeply and are very committed to being great parents to their daughter."

He blamed pressures of work for their break-up, saying: "You can never be stunned by what happens in Hollywood - I learned that when we were dealing with Michelle's career when she was younger. Michelle was grown up at 16 and, just like Heath, her life has had an extremely fast pace to it.

"I feel tremendously for her and for him, and hope they will find what they want in life."

The split has not yet been officially confirmed by the couple's publicist but they are believed to have parted amicably several weeks ago.

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