Brokeback Mountain star Heath Ledger has been found dead at a Manhattan apartment.

Police are investigating the death of the 28-year-oldAustralian who was nominated for an Oscar in 2006for his role in Ang Lee's Western.

Reportssuggests a possible drugs overdose.

The Perth-born actor appeared in Todd Haynes' Bob Dylan film I'm Not There for which his fellow Australian Cate Blanchett was today nominated for a best supporting actor Oscar.

He was due to find a new army of fans this year in his role as The Joker in Christopher Nolan's Batman film The Dark Knight. Images of Ledger as a sinister-looking updated Joker had piqued fan interest in recent months.

The versatile star established himself in films including The Patriot, Monsters Ball and A Knight's Tale.

More recently he starred inLasse Hallstrom's Casanovaand The Brothers' Grimm, directed by Terry Gilliam, with whom he was shooting his latest film The Imaginarium of Doctor Parnassus.

But he will probably be best remembered for his role as Ennisin Brokeback Mountain, a role which also earned him best actor nominations at the Golden Globes and BAFTAs.

Meanwhile, there is no word yet about the fate of Doctor Parnassus. The project,produced by William Vince, Amy Gilliam, andSamuel Hadida, had recently wrapped the London portion of its shoot after a December start. The team was readying its work in Vancouver.

The modern-day fantasy adventure, about a travelling theatre troupe that transports its audience, also stars Christopher Plummer, Tom Waits, Lily Cole, Andrew Garfield and Verne Troyer.

Mandate International is the sales agent for the film, with Hadida's Paris-based Davis Film handling the financing.

Ledger plays Tony, an outsider who charms the Doctor's daughter Valentina, without knowing that her father has promised her to the Devil on her upcoming 16th birthday.

Davis Film hasn't yet commented on what will happen to the film after Ledger's death.