Did Heath Ledger Base His Joker On Tom Waits?

This video has been kicking around online for a couple years, but having just seen it for the first time, I thought I'd share it with you, the reader, in case we both missed it. It's a 1979 clip from Australian television's The Don Lane Show, in which a 29 year-old, highly affected Tom Waits squirms through an interview to promote his score for the film On The Nickel. Get to the exchange about two minutes in and tell me Heath Ledger didn't somehow see this clip before filming The Dark Knight...

The American-born Lane is obviously a gushing fan, which may be why Waits is so uncomfortable, and I almost wish I didn't see this clip on account of how phony Waits comes off in it (Waits didn't sound like this in subsequent interviews). But what the hell is the deal with this appearance and Ledger's Joker? Ledger and Waits appeared together in The Imaginarium of Doctor Parnassus, so maybe they knew each other and it was some kind of in-joke. Or maybe it's been flat-out confirmed that the similarity is intentional on a commentary track or interview somewhere? (I can't imagine there's any detail about The Dark Knight that hasn't been over-examined into atoms by fans.) Can it possibly be a coincidence? Is it better or worse knowing that cosplay nerds ran around for a year doing Tom Waits impressions in clown paint and runny mascara?