Australian actor Heath Ledger has been found dead in his Manhattan apartment, possibly of a drug overdose.

Police spokesman Paul Browne has confirmed Perth-born Ledger, 28, was found dead by a housekeeper at his apartment in the trendy SoHo neighbourhood.

" We are investigating the possibility of an overdose," Mr Browne said.

According to Mr Browne, the housekeeper found Ledger at 3:26pm (7:26am AEDT) and tried to wake him for his appointment to have a massage.

As far as Mr Browne knows, only Ledger and the housekeeper were in the apartment.

Lieutenant John Grimpal from the New York Police Department says drugs were found at the scene, but investigators are yet to determine how he died.

" There was some type of drugs found," he said.

" Unknown what type right now.

" The medical examiner will determine if that ... caused his death or if something else caused his death."

The handsome star and his long-time companion, actress Michelle Williams, separated last year.

Williams is mother of the actor' s young daughter, Matilda.


Tributes

Ledger was nominated for a best actor Oscar for his role as a gay cowboy in Brokeback Mountain. He did not win. The award went to Philip Seymour Hoffman for his role as Truman Capote.

The film' s director, Ang Lee, had hailed Ledger' s performance as a " miracle" of acting, reminiscent of a young Marlon Brando.

Margaret Pomeranz from ABC TV' s At The Movies says she is devastated by the news.

" I am so upset ... he' s such a talented boy and really I think a beautiful soul," she said.

" I think to choose the roles he' s chosen showed just such intelligence."

Neil Armfield directed Ledger in Candy.

He says he was an actor of incredible power and potential.

" He was always a complex and complicated man to work with but ... just a master ... just so passionately concerned to get it right."

Ledger' s other film credits included A Knight' s Tale, The Patriot and Monster' s Ball.

He was one of several actors playing a role representing Bob Dylan in I' m Not There.

He will appear as The Joker in the next Batman film The Dark Knight. The film is currently in post-production.

Fellow Australian actor Samuel Johnson says his latest performance was said to have been one of his best.

" His portrayal of The Joker in the new Batman [film] was going to rival Jack Nicholson' s in the original," he said.

" I' ve heard nothing but positive feedback about his latest job.

" I' m distraught about this ... I think we' ve lost one of the best young actors Australia' s produced - if not the best."


' Unusual talent'

Ledger first came to prominence by acting as a homosexual athlete in the little-known Australian series Sweat in 1996.

He played a gay cyclist in the soap, set at the Western Australian Institute of Sport.

The creator and writer of the series, John Rapsey, says it was clear that Ledger - then a 16-year-old sports champion and high school dropout - possessed an unusual talent.

" He himself had absolutely no problem playing the role. He handled all of that with great aplomb," Rapsey told AFP.

" What was noticeable about him was he was concentrated, very quiet, and you could see that he was really observant of other people."

Ledger, who never attended acting school and who left his home state of Western Australia for Sydney as a teenager, credited his instincts with his success.

" The one thing that' s got me to where I' m sitting is my instincts, you know, and I' m impatient. I didn' t want to wait for years to work. I wanted to just get out there and do it," he said in 2001.

At 19, Ledger left Sydney for Hollywood.

His standout talent was spotted by Mel Gibson when auditioning 500 actors for the role of his son in The Patriot. The casting was Ledger' s first big-time break and led to his leading role in A Knight' s Tale.

Fellow Australian actor Gibson has described Ledger as possessing " the unknown factor" that " sort of lights up the screen" .

Ledger continued his steady impact on Hollywood, with a small role in Monster' s Ball (2001), followed by the lead in The Four Feathers (2002), Australian drama Ned Kelly (2003) and The Brothers Grimm (2005).

At 26, the Australian was the youngest nominee for the best male actor category and the outside chance to take the statue away from fellow contenders Hoffman, David Strathairn, Joaquin Phoenix and Terrence Howard.

This month, Ledger had been working on his latest movie, The Imaginarium of Doctor Parnassus, directed by Terry Gilliam.

It was due to be released next year.