Eminem has been invited to perform at the former South African president Nelson Mandela’s 90th birthday party in June.According to New York’s Daily News, Em was contacted by event coordinator Brian May - formerly of the rock band Queen - about a month ago to appear at the South African freedom fighter’s celebration.The bash is to be held in London this June and will be hosted by Will Smith and organizers have extended initations to Slim Shady and Stevie Wonder to perform.If Eminem accepts, it will mark the first time Em has performed live since his surprise appearance at the 2006 BET Awards, where he joined Busta Rhymes to perform “Touch It.”