Showing up on the red carpet in the same dress is a Hollywood no-no. And rocking matching hair hues isn't much better.
Of course, the pink 'dos are nothing new for either singer—plus, Katy wore hers up while Nicki rocked a Barbie-style wig—but it's hard to find enough room on the red carpet for two identical "notice me!" hair colors.
So who wins bragging rights for her Pepto hair and who should head back to the color wheel to try something different?