Diary is an American documentary television series that premiered February 16, 2000, on MTV.
The show's opening titles begin with the slogan "You think you know ... but you have no idea."
The series follows celebrities through their everyday lives. Some of the celebrities featured include Jay-Z, Aaliyah, Beyoncé Knowles, Marilyn Manson, Brandy, Britney Spears, Christina Aguilera, Lindsay Lohan, Blink-182, Green Day, Sum 41, Hilary Duff, Korn, Jack Black, Chris Rock, Backstreet Boys and Nas.