Christian Bale lost about 70lbs in 3 months for the MachinistWe all love to be at the top of our craft, and actors and actresses are no different. In this collection of snaps you can see those hard working screen stars before and after they made big changes to their bodies. Think about what it would be like to lose 50lbs to get a part, or gain 30. You can work out to get bigger muscles and toned, but losing and gaining weight is real work.

Charlie Sheen built muscles for Hot Shots! Part Deux
Russell Crowe gained 63lbs for Body of Lies
Jake Gyllenhaal gained 25lbs of muscle for Jarhead
Ben Stiller build some muscles for Tropic Thunder
George Clooney gained 30lbs of fat for Syriana
Linda Hamilton toned up really well for Terminator 2
Hilary Swank put on a lot of muscle of Million Dollar Baby
Mr. Stallone put on about 40 lbs of fat for Copland
Tom Hanks lost about 50lbs for his movie Cast Away
Renee Zellweger gained a lot of weight for both Bridget Jones movies
Demi Moore gained muscle for G.I.Jane doing one arm pushups
Jessica Biel gained some really defined muscles for Blade Trinity
Matt Damon lost 40lbs for Courage Under Fire
Gerard Butler gained muscle for 300
Ed Norton (yeah the skinny dude) gained muscles for America History X
Charlize Theron became ugly and gained a lot of weight for Monster
Eric Bana Ballooned up for his role in Chopper
Ryan Renolds packed on some serious muscle for the Blade movies