He did. 
http://www.nydailynews.com/news/us_world/2008/01/31/2008-01-31_heath_ledger_caught_on_drug_tape.html
Heath Ledger caught on drug tape Thursday, January 31st 2008, 11:29 AM
Frames from a video show Heath Ledger at a drug-filled 2006 Hollywood party.
A shocking video has surfaced showing a guilt-ridden Heath Ledger at a Hollywood drug party confessing to strangers he was a pothead for most of his life.
The dark and grainy tape shot at the Chateau Marmont hotel in Los Angeles was obtained by Australia's Channel 9, which plans to air it tonight despite an uproar from the Hollywood community.
The segment shows a man snorting what appears to be drugs off a table.
The video, shot after the Screen Actors Guild Awards on Jan. 29, 2006, shows Ledger talking at a private party at the same hotel where comic actor John Belushi died of an overdose.
"I'm going to get serious s--t from my girlfriend," Ledger tells his companions. "We just had a baby three months ago.
Ledger's companion, actress Michelle Williams, and baby daughter, Matilda, were said to be upstairs in their bungalow while he partied.
"I shouldn't be here at all," he tells the guests, and then offers the admission: "I used to smoke five joints a day for 20 years."
Ledger was found dead Jan. 22 in his SoHo apartment at age 28. The cause of death has not been released, pending toxicology reports. Six different prescription drugs were found in the home.
