What was he thinking?

David Bowie duets with Cher:

Everything seems normal, albeit slightly cabaret, until around 1min 20secs and then things go downhill very quickly.

This was 1975, with Bowie still enormously cool and creative. But, to give him his credit, he appears to be having a really good time - check out the dancing just after the four minute mark.

Is there anyone today whose credibility is similar to what Bowie's was then, who would dare to do anything this uncool? What is the modern equivalent of a variety show duet with Cher, anyway?