Revealing: Before They Were Famous Celebrity Auditions – Jim Carrey, Jimmy Fallon, Seth Rogen and More! [VIDEOS]

What does it take to nail an audition for a big movie role? Take a look at some our favorite celebrities giving it their all to get the part in these rare audition clips.

Watch Jimmy Fallon, Seth Rogen, Miley Cyrus and others deliver thier lines behind the scenes to the producers and directors. It's a revealing process to watch.

..And see Jim Carrey really get into character to land the role of Andy Kaufman in the Man on the Moon: