Rihanna & Chris Brown's Music Collaboration: Too Sexy?

The 2009 Grammys marked the beginning of a domestic violence drama that revealed a darker side to Chris Brown's relationship at the time with Rihanna.

But nearly three years to the day, Brown, 22, and Rihanna, 24, were again spending time together on music's biggest night – and it was an unexpected collaboration.

The former couple, whose recent friendly behavior is no secret on Twitter, both hit the studio last week to record parts on each other's songs, which were released late Monday.