Who first said: "It ain't over 'till the fat lady sings"?

Halmshaw, Ferriby, UK

• I have heard this attributed to Sam Goldwyn. As for the fat lady, I've no idea who she was or what she was singing.

  Alasdair Patrick, Dana Point, California, USA

• The fat lady.

  Daniel Morgan, Boston US

• Tha fat lady in question is not from Baseball, America is not the centre of the Universe. That said, the fat lady in question is the bird that sings The Valkyrie at the end of Verdi's opera.

  Mr H, Glasgow

• I have always been told that the originator of this was baseball's Yogi Berra, also credited with "It ain't over till it's over" and "90% of the game is one half mental". As I type this though, I realize that I have probably been told wrong, since surely Yogi never attended an opera in his life.

  Brandon Thornburg, Portland, OR(formerly Poynton, Cheshire) USA