Heath Ledger HLEDGER020606_03.jpg Drugs may not have played a role in Heath Ledger's untimely demise - but it's starting to sound like they played a frighteningly huge one during his life!

Us Magazine is reporting that back in 2006, Ledger's fiancee Michelle Williams actually drove the troubled actor to the famous Promises rehab center - only for Heath to refuse to be admitted once they arrived!

A source close to the story told the magazine that Williams had borne witness to Ledger partaking in all sorts of druggy delights, "including cocaine, heroin and "a variety of pills."

Of course, when confronted with the check-in desk at Promises, Heath suddenly seemed capable of stopping, swearing to Michelle that he'd clean up his act.

Apparently, even Heath's young daughter Matilda - then only five months old - couldn't curb his appetite for destruction.

Maybe that's why, when the couple split up in 2007, Michelle demanded that Heath be drug-tested before his visits with Matilda!