Having kept a dignified silence since her split from Chris Brown, Rihanna has now hit back with a song apparently laying into the R&B star. Silly Boy, which features guest vocals from Lady Gaga was posted online by Rihanna’s good friend Kanye West. The feisty lyrics include the lines, "I said I'm not coming back. You fooled me once but you can't have that ego turning. Just too bad for you, that when you had me. Didn't know what to do, she's over you. Cause you had a good girl, good girl, girl. That's a keeper. You had a good girl, good girl but didn't know how to treat her. So silly boy get out my face. Why do you like the way regrets taste?" Go girl!