The Umbrella singer turned 23 on Sunday and celebrated with a celebrity bash. But pal Katy Perry couldn't make it because she has started her world tour.
Writing on Twitter, Rihanna said, 'Go grawl, its ya birthday, ITS PARTY TIME! All my best friends are here!!!! And my BRO!! Wish u cud see how SICK this s**t is!!! Stay tuned.'
Katy replied, 'Happy birthday boo. Wish I could b there to blackout! Luv U!'
But Rihanna told her not to waste time feeling bad after she missed her October wedding to Russell Brand. She Tweeted, 'B**ch are u kidding? I missed ur WEDDING!! This is small stuff boo! When work calls.'