Us Weekly and People magazine both reported Ledger and actress Michelle Williams, the mother of his 2-year-old daughter, Matilda, split up last year because Ledger was abusing drugs and wouldn't get professional help.
However, Ledger's representative Mara Buxbaum told the New York Daily News that Us Weekly's account of how Williams drove Ledger to a Malibu rehab to be treated for his addiction to cocaine and heroin -- but Ledger refused to get out of the car -- was "fabricated ... just one lie among many."
While one source told the Daily News, "I only saw him smoke pot," another insider painted a different picture.
"It was evident Heath liked to be down. Naomi Campbell threw a party a few years back where he stayed in her closet the whole night and only allowed certain guests to enter," a second source said.
"The speculation is heinous," Buxbaum told the Daily News.
However, a video allegedly showing Ledger at a 2006 party talking about how he smoked marijuana for years has been making the rounds, the Daily News said in a separate story.
Two U.S. tabloid TV shows -- "Entertainment Tonight" and its sister show "The Insider" -- have said they will not air the video as planned out of respect for Ledger's grieving family, E! Online said.