Joan Rivers -- Write This on My Tombstone ...

Joan Rivers spoke prophetically about what she wanted on her tombstone one month ago -- and the words she chose were classic Joan.

She was at LAX back in August when a photographer -- with whom she clearly had a good relationship -- jokingly asked about her health ... and what she would want her epitaph to say.

Check it out ... it's simple, honest -- and no one could possibly argue against it.