50 Cent's Final Lap tour stopped in Detroit on Sunday night, and Eminem surprised the crowd by coming out to perform 'Paitently Waiting' and 'Crack A Bottle' with his longtime friend and collaborator. “Don’t fu-king act like you ain’t know I was gonna be here,” Eminem told the audience. “Detroit, make some noise for one of the best friends I’ve ever known: 50 Cent. And also, make some noise for hip-hop’s 50th birthday, y’all.” Eminem signed 50 Cent to Shady Records before the release of Get Rich Or Die Tryin’ in 2003. They've since collaborated on songs like “Gatman & Robbin,” “My Life” and “Is This Love.” 50 Cent shared earlier this year that Eminem approached him about getting back into the studio with Dr. Dre, but no concrete release plans have been revealed yet.