Tom Waits Interview / Heath Ledger's Joker

"Few performances are as memorable as Heath Ledger’s terrifying, smirking inevitability as The Joker in The Dark Knight, a role which earned him a posthumous Oscar. Many people have tipped us to a 1979 interview of Tom Waits which is eerily similar to The Joker’s voice, inflections, and mannerisms. Thinking Heath Ledger’s inspiration for The Joker may have been Tom Waits isn’t as far-fetched as it seems. The two worked together in Terry Gilliam’s The Imaginarium of Doctor Parnassus, a movie which took so long to develop that it’s conceivable the two could have met at some point before The Dark Knight filmed."

Interview: Tom Waits interview

Searched, nothing came up, but I'm sure this has been discussed at some point on here before. Saw these video comparisons a while back and after watching the Dark Knight again today.. The similarities are uncanny.

What's your take? Inspiration or not?