May 21, 2011 - Ethan Miller/Getty Images North America more pics like this »
Prev 23 of 26 Next
23. Pillow Fight

Rihanna and Britney performed at the Billboard Music Awards in May 2011, and their steamy collaboration was the talk of the show. Both gals came out pantsless, then they proceeded to get into a super sexy pillow fight during their rendition of "S&M."