8. Ryan Gosling - The Lovely Bones
Unlike every other actor on this list, Ryan Gosling didn't actually get to play the role he was cast in, with his desperation to create a character detached from himself ultimately resulting in him being fired from the production.
Gosling was originally cast as Jack Salmon in Peter Jackson's 2007 supernatural thriller The Lovely Bones, though the actor himself harboured concerns that, at just 26 years of age, he simply wouldn't be believable as the father of a 13-year-old Saoirse Ronan.
And so without consulting Jackson, Gosling decided to gain 60 pounds by drinking melted Haagen Dazs ice cream whenever he got thirsty, all in an attempt to look more rugged and homely.
But when he arrived to set in this state, Jackson was allegedly less than pleased and dismissed the actor, replacing him with the more age-appropriate Mark Wahlberg.
Gosling said of the experience:
"It was a huge movie, and there's so many things to deal with, and [Jackson] couldn't deal with the actors individually. I just showed up on set, and I had gotten it wrong. Then I was fat and unemployed."
You can certainly appreciate why Gosling felt the desire to transform himself and get away from his hunky heartthrob appearance, though doing so without running it by the director clearly wasn't the smartest course of action.