In Love with a German Filmstar

The Pet Shop Boys are actually going to release a cover version of this enigmatic song
Enigmatic because I can´t figure out who the hell the singer fell in love with. Peter Lorre? Konrad Veidt? Max Schreck? Curd Jürgens?
The cover-photo of the PSB production which is sung by Sam Taylor-Wood as well as the original video suggests Marlene Dietrich. But I was never content with this.