It'll only take daily six-hour workouts and 14,000 sit-ups a week for you to get ripped like Jake Gyllenhaal for 'Southpaw' (after he shed 30 pounds for 'Nightcrawler' last year). Click on for more remarkable transformations stars made for their roles. 

Angelina returned to the "sexy assassin" role similar to her character from 'Mr. & Mrs. Smith' as Fox in 'Wanted.' Playing a beautiful killer, Jolie shows off her fighting and shooting skills as well as her very sculpted and toned body in this 2008 release.

Fun Quote: On physical roles: "Harrison [Ford] is doing it, and he's doing it well. It looks like I've got some more time."

To play a scary escaped convict convincingly, De Niro committed to 2-3 hours of weight training 6 days a week for 6 months, plus 45 minutes of cardio AND a warmup of pull-ups and lunges. At 48, the star had single-digit body fat.

It took six months of training six days a week for Pitt to get into Greek-statue shape for his role as Achilles, doing a variety of circuit training and cardio plus eating healthy. He has said it was the hardest workout he'd ever done.

Fun Fact: Pitt claimed the filming was torturous for him due to the fact that he had to quit smoking.

Norton also took a turn at bulking up his thin physique, employing a high-protein diet and squats/presses to morph into a neo-Nazi skinhead, a role that also earned him an Oscar nomination. 

From 'Meet the Parents' to 'Meet the Guns!' -- arms that is! Stiller bulked up for his comedic role as action star Tugg Speedman in the hilarious 'Tropic Thunder,' which he also directed.

Fun Fact: According to Stiller, his character is partially based on a young Sylvester Stallone.

Rourke's acclaimed role as Randy "the Ram" Robinson had him training for months before shooting to pack on 30 pounds of muscle. His former boxing career didn't help much in the wrestling ring, so on top of weight training and cardio, he took on actual wrestling practice. By the end of it, his trainers told him he was better than 80 percent of the WWF guys.

 

He may be wearing a skirt, but don't underestimate this coliseum champ. He wowed fans with his brawn as well as his acting chops in his Oscar-winning role, which required he lose 50 pounds of fat gained for his previous role, 'The Insider.' He did this by sword fighting, lifting weights and working on his farm.

Bale weighed only 110 pounds during the filming of 2004's 'The Machinist' but he gained back a lot of his lost weight via an intense exercise regimen that bulked him up to 210 pounds only a year later.

Fun Fact: According to DC Comics, Batman stands 6'2" and weighs 210 pounds. Christian Bale stands 6'0-1/2" (according to his IMDb profile) and at the time of filming weighed 210 pounds.

Swank deems boxing "the most intense workout you can ever experience." Her training included drinking egg whites, flax oil and protein shakes, boxing for two-and-a-half hours, and an hour and a half of lifting six days a week.

Fun Quote: "I bloodied this guy's nose one time and I turned around to my trainer after the round was over and I smiled. And I didn't say sorry. It was just an amazing feeling."

The former Fresh Prince gained 35 pounds to match Ali's 220, and much of the film shows Smith taking real punches. Charles Shufford, who plays George Foreman, was given license to make his jabs as real as possible.
 

Maguire used the same trainer as Brad Pitt did for 'Troy' and his twice-daily, six-days-a-week, six-months regimen was also similar, to get him ripped and ready to play the webslinger in a skintight suit.

Transforming into the warrior king of Sparta just about put Butler through hell; he trained with a world-class mountain climber and Venezuelan bodybuilder. It went a little like this: 25 pull-ups, 50 deadlifts, 50 push-ups, 50 jumps on a 2-foot box, kettle-bell arm presses.... okay, we'll just stop there. 

Craig quit smoking and had a personal trainer to get into shape to portray James Bond -- the same personal trainer hired to work with Pierce Brosnan on The World Is Not Enough and Die Another Day. Rather than isolate muscle groups each day, he did full-body circuit training five days a week and changed his diet to lose weight and build muscle.

For 'G.I. Jane,' the ever-youthful star took on Navy SEAL and obstacle-course training, as well as running, swimming, push-ups, sit-ups and squats.

Fun Quote: "I want them [her daughters] to know that being thin does not equate to happiness."

To make her fight against the machines authentic, Hamilton underwent judo and heavy-duty military training to portray Sarah Connor. She also learned how to change mags, load clips and verify kills. Hey, if mankind depended on your boy to lead the resistance, you'd get whipped into shape, too!

Remember way back when Matt made a name for himself with his pal Ben Affleck in 'Good Will Hunting'? He didn't have much meat on him then. To assume a spy's identity, he bulked up and actually took up boxing for the acclaimed 'Bourne' franchise.

Fun Fact: Damon has gone the other way in the extreme as well, dropping an unhealthy 40 pounds for his role in 'Courage Under Fire.'

Underneath the fedora and overcoat is a slimmed-down Seth Rogen, who hired personal trainer Harley Pasternak and hit the gym to lose 30 pounds. Hard to believe he's the same huggable teddy bear from 'Knocked Up.'

Fun Quote: "I exercised to the point where he made me throw up."

When he's not dripping in fake blood and covered in gashes for filming, Korean pop star Rain flaunts a well-defined bod. He reportedly ate only chicken breast and veggies for eight months and trained 10 hours a day to get ripped. We're in for some cool martial arts scenes, since the coordinating stunt team behind 'Ninja Assassin' is 87 Eleven, who also worked on 'Bourne' and 'Matrix' films.

There's been a lot of body sculpting in the vampire-killing business, but back in 2003 it was just as common. Reynolds boasted a 20-pound muscle gain and shredded his body fat to 3 percent in 5 months.

Jessica Biel's always been on the lean side, but she toned up for her vampire-hunting role with a combination of running, stair jumping, weight lifting and lunges to work out her entire body.

Fun Quote: "There is so much pressure to look a certain way in this town. But it's nice to have a little meat on you, and I hope I inspire women to appreciate their muscular calves."

Coming off a Broadway show, Jackman was fairly slight and had just five months to bulk up for the brawny movie character. His trainer had him lift extra-heavy weights at low repetition as well as do low-intensity cardio and interval training.

Even before slimming down and shaping up for her role as Black Widow, Scarlett flaunted a voluptuous physique of envious proportions. She says it took months of stunt training along with traditional weightlifting and core strength exercises.

Fun Quote: "The goal was the Lycra catsuit."

It was only fitting for RDJ to go all out for a major comeback into superstardom. The unlikely superhero gained 20 pounds of muscle weightlifting and had to wear an extra 40 in his iron getup. For 'Iron Man 2,' he worked with star trainer Brad Bose, who helped come up with uncoventional exercises involving modified wheelbarrows and fire hoses.

Jake's come a long way from the troubled teenager look of 'Donnie Darko.' To portray the Persian prince from the successful 'Sands of Time' video game, he not only had to get a tan, he had to beef up and train for the amazing Parkour stunts that've become the game's unique signature style.

And the winner is, you guessed it, Taylor Lautner, who won by a landslide. You have to hand it to the 17-year-old; he had a bit part as scrawny Jacob Black in Twilight, and when it looked like he might get replaced for New Moon, showed Hollywood what he was made of. To gain 30 pounds and an 8-pack, he adhered to a body-sculpting plan that consisted of eating every 2 hours and working out every day. Congrats to Taylor for securing his part, and giving Team Jacob something to scream for!