A Diamond Is Forever
- Brand
- De Beers
- Copywriter
- Frances Gerety
- Agency
- N. W. Ayer & Son
- Year
- 1948
- Country
- USA
Written by copywriter Frances Gerety of N. W. Ayer & Son in Philadelphia for De Beers, which had been an Ayer client since 1938. The line has appeared in De Beers advertising since 1948, and in 1999 Advertising Age named it the slogan of the 20th century.