In order to promote its over the shoulder boulder holder, Wonderbra developed National Cleavage Day (celebrated religiously in Britain). There's no shortage of bosom-baring stars in Hollywood. These ladies have it and flaunt it.

From Katy Perry (who was banned by "Sesame Street" for showing too much of it) to "Mad Men" star Christina Hendricks (who has repeatedly insisted hers are real), we salute the stars with the best cleavage.

We think the US should have their own National Cleavage Day, too, so check out Starpulse.com's list of the top 10 famous gals who like to show off their girls!

Let us know if your favorite cleavage-baring celebrity didn't make the list...