Where did the quote about diamonds came from?

The quote "Diamonds are a girl's best friend" is often attributed to the 1953 musical "Gentlemen Prefer Blondes", specifically the song "Diamonds Are a Girl's Best Friend". The song was performed by the character Lorelei Lee, played by Marilyn Monroe, who sings about her love for diamonds. The phrase became famous after the movie's release and became widely used in popular culture.