A duet with SSJ

The cover album Southside Johnny is preparing has been mentioned here before a couple of times and now another interesting detail has surfaced in an interview with The Star Ledger: apparently, we have a duet with Tom Waits himself to look forward to.

Q. So La Bamba is the producer?
He's the arranger, and I'm the singer, as they say. And we have a duet with
Tom Waits, too. He and I sing together, which is not what one would call
mellifluous, but it's effective.

Q. What song is that?
,,Walk Away'', a song that he never recorded.