This week Rihanna celebrated the 15th anniversary of Pon de Replay, the first single from her debut album, Music of the Sun. And not only that, but Britney Spears also celebrated a musical birthday too. Her sophomore album, Oops!… I Did It Again turned 20! Who would have thought those two little pop songs would transform them into such music/style icons. And all these years later, people are still fanning out over them. So, let's flash it back to those two singles, and their very sexy collaboration, S&M.

Rihanna - Pon de Replay

Britney Spears - Oops!...I Did It Again 

Rihanna & Britney Spears - S&M (remix) Billboard Music Awards 2011