A lot of actors take their job very seriously and really make an effort to get deep into their character. Here we have some celebrities who either gained weight (i.e. became fat), lost weight (i.e. got really skinny) or got fit (i.e. made some muscle)
20. Charlie Sheen built muscles for Hot Shots! Part Deux
19. Russell Crowe gained 63lbs for Body of Lies
18. Jake Gyllenhaal gained 25lbs of muscle for Jarhead
17. Ben Stiller build some muscles for Tropic Thunder
16. George Clooney gained 30lbs of fat for Syriana
15. Christian Bale packed on quite a bit of muscle of Batman Begins
14. Linda Hamilton toned up really well for Terminator 2
13. Hilary Swank put on a lot of muscle of Million Dollar Baby
12. Mr. Stallone put on about 40 lbs of fat for Copland
11. Tom Hanks lost about 50lbs for his movie Cast Away
10. Renee Zellweger gained a lot of weight for both Bridget Jones movies
9. Demi Moore gained muscle for G.I.Jane doing one arm pushups
8. Jessica Biel gained some really defined muscles for Blade Trinity
7. Matt Damon lost 40lbs for Courage Under Fire
6. Gerard Butler gained muscle for 300
5. Ed Norton (yeah the skinny dude) gained muscles for America History X
4. Charlize Theron became ugly and gained a lot of weight for Monster
3. Eric Bana Ballooned up for his role in Chopper
2. Ryan Renolds packed on some serious muscle for the Blade movies
1. Christian Bale lost about 70lbs in 3 months for the Machinist
20. Charlie Sheen built muscles for Hot Shots! Part Deux
19. Russell Crowe gained 63lbs for Body of Lies
18. Jake Gyllenhaal gained 25lbs of muscle for Jarhead
17. Ben Stiller build some muscles for Tropic Thunder
16. George Clooney gained 30lbs of fat for Syriana
15. Christian Bale packed on quite a bit of muscle of Batman Begins
14. Linda Hamilton toned up really well for Terminator 2
13. Hilary Swank put on a lot of muscle of Million Dollar Baby
12. Mr. Stallone put on about 40 lbs of fat for Copland
11. Tom Hanks lost about 50lbs for his movie Cast Away
10. Renee Zellweger gained a lot of weight for both Bridget Jones movies
9. Demi Moore gained muscle for G.I.Jane doing one arm pushups
8. Jessica Biel gained some really defined muscles for Blade Trinity
7. Matt Damon lost 40lbs for Courage Under Fire
6. Gerard Butler gained muscle for 300
5. Ed Norton (yeah the skinny dude) gained muscles for America History X
4. Charlize Theron became ugly and gained a lot of weight for Monster
3. Eric Bana Ballooned up for his role in Chopper
2. Ryan Renolds packed on some serious muscle for the Blade movies
1. Christian Bale lost about 70lbs in 3 months for the Machinist
