It was for a film she was in by Martin Scorsece, called "New York, New York"? But it was for her to sing in the movie. Great song. Then it became Frank's song. Somehow.
Yes, I have read that somewhere before. I haven't heard Liza's version and everybody associates the song with Frank Sinatra because his version became a hit. I knew it was a film theme song, although I haven't seen the film myself. I have seen videos of it for sale over the years.
