10 of the Craziest Celebrity Weight Gains and Losses

The stars of Hollywood never cease to surprise with their drama, whether it be on screen or off — especially when it comes to their weight. On-camera extreme weight gains and losses are incredibly shocking, but also make you realize just how dedicated these actors are to their craft. We've seen an array of stars either bulk up or slim way down for a variety of roles, and now we can add Chris Hemsworth to the list. He went from being ripped to wiry for his role in "The Heart of the Sea." The 32-year-old plays crew member Owen Chase who has been lost at sea for three months. The actor posted a picture on Instagram of his crazy change in appearance, saying , "Just tried a new diet/training program called "Lost At Sea". Wouldn't recommend it.."

To look this thin, Chris took on the "starvation diet" in 2013, consuming only 500-600 calories a day. Here's a look back at some other crazy transformations as well.

50 Cent

50 Cent went from a buff rapper to a committed actor who opted to slim down by 56 pounds to play a cancer-stricken football player in "Things Fall Apart." He was on a liquid-only diet and his exercise consisted of daily three-hour treadmill walks.

Christian Bale

Christian Bale lost more than 60 pounds to appear this gaunt for his role in "The Machinist." He had to bulk up soon after, however, to play Batman.

Matthew McConaughey

To play an AIDS sufferer in "Dallas Buyers Club," Matthew McConaughey shed 42 pounds. He did this by eating little-to-no food. “It was tough going, I’m not going to lie,” he admitted. “The dieting was pretty hardcore. I was losing 7lb every week.”

Natalie Portman

Natalie Portman lost 20 pounds for her role in "Black Swan." The actress, who is already very thin in real life, shocked people with her even more petite frame.

Jonah Hill

To shoot "21 Jump Street,"  Jonah Hill had to slim down, as he played an undercover police officer alongside already very fit Channing Tatum.

Gerard Butler

To bulk up for his role in "300," Gerard Butler had to do some serious gym training designed by personal trainers. Source: Mirror [caption id="attachment_120127" align="alignnone" width="100"] @BodyRockOfficial[/caption] [caption id="attachment_120128" align="alignnone" width="100"] @BodyRockTV[/caption]