The footage is understood to have been shot two years ago at Los Angeles celebrity hangout Chateau Marmont at a January 29 (2006) party following the Screen Actors Guild awards - where Ledger had missed out on two awards for Brokeback Mountain despite being favourite in both categories.
Ledger had appeared at the ceremony alongside his girlfriend Michelle Williams but she did not attend the private party and was reportedly sleeping in a room upstairs with the couple's daughter Matilda.
The footage, which was taken through a window into a hotel room, showed Ledger talking and shows at least one guest sniffing a "cocaine-like" substance off a drug-filled table with a rolled up bill in his hand. At one stage, Ledger's face is noticeably twitching as he speaks.
