By Aly Semigran, Hollywood.com Staff

When It's Always Sunny in Philadelphia star Rob McElhenny transformed his character from the dim-witted, morally bankrupt Mac to a heftier version in Season 7, better known as ""Fat Mac"" the actor explained why he opted to pack on the pounds for the show. ""It came when I was watching a very popular sitcom, and I noticed the people were getting better and better looking as the seasons were going on,"" McElhenney explained in 2011 regarding the concept and execution of ""Fat Mac.""

It's a pretty accurate observation, really, from someone who eats rum ham. From the cast of Friends getting significantly better looking (and dressed) during the span of the show's wildly successful run (including Jennifer Aniston's transformation from Girl Next Door to full-on sex symbol) to reality stars making complete image overhauls (American Idol's Clay Aiken, Teen Mom's Amber Portwood) there have been so many memorable television transformations. Check out our gallery and recall which stars changed right before your eyes.

Launch gallery now!

[Photo credit: Warner Bros. Television]

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TV Transformations