One burst on the scene in the late 1990s and became one of the most successful pop artists of all-time, dominating sales and headlines throughout the next decade.
The other made a name for herself in the late 2000s and, while her career is still in its early stages, looks poised for a decade comparable to that of her predecessor.
It's little surprise that Britney Spears and Lady Gaga are battling for Twitter supremacy, given their hit songs, controversial images and impact on popular culture.
Right now, Gaga leads at 5,713,469 followers. Britney has 5,695,008. Ashton Kutcher, who Spears just passed to temporarily claim the #1 spot, has 5,568,785.
Who would you rather ... follow on a social network?
Buoyed by a year and a half of smash hit singles, outrageous outfits and Lady Gaga hermaphrodite rumors, the "Bad Romance" singer leads on Facebook as well.
Spears, whose celebrity status has proved as bulletproof as it is long-lasting and enormous despite various mishaps, isn't doing too shabbily on that site, either.
Who will reign supreme as the Queen of All Social Media? At least until Justin Bieber decides he will become #1 and does so immediately? Only time will tell.