Chris Brown and Big Sean
Over the weekend, Chris Brown announced that Big Sean would be joining him, Kelly Rowland, T-Pain, and Tyga on the FAME tour:

Big Sean just got added to the tour! Gonna be really amazing!
August 20, 2011 6:58 PM via Twitter for iPhoneReplyRetweetFavorite
@chrisbrown
Chris Brown

This is shaping up to be huge. Wish they were coming to Denver. -_-