After being on the air for 15 years, CBS has decided to end their successful series CSI: Crime Scene Investigation! This is really sad news, especially since a bunch of your favorite celebrities have been on the show \u2013 most of them even got their start on it! \n\nCLICK HERE TO SEE CELEBRITIES WHO GUEST STARRED ON 'NCIS' BEFORE THEY WERE FAMOUS!\n\nLuckily, it's not leaving without a bang. The show will be ending with a two-hour TV movie in September, which promises to be emotional and memorable.\n\nClick through the gallery to see 26 celebrities you had no idea were on the show, then let us know who you're the most shocked to see. Did you watch any of the episodes?