Christian Bale has to be the most dedicated method actor of his generation, since he regularly undergoes drastic body transformations for roles.

The most infamous example of this was his extreme weight loss for 2004’s The Machinist, where the actor shed 63 pounds in a matter of months.

He only stopped when doctors warned him that he was at serious risk of dying.

Bale’s emaciated physique in this film is haunting, and it became the most talked about aspect of the movie.

After dropping more than 50 pounds to play the role of an HIV-positive trans woman in Dallas Buyers Club, Leto put it all back on and gained even more to play Mark David Chapman in Chapter 27.

Leto put on over 70 pounds, all of which came from drinking microwaved pints of ice cream mixed with olive oil and soy sauce.

The sudden weight gain strained Leto’s body that he developed gout, which forced him to use a wheelchair.

Before Christian Bale, De Niro was the undisputed king of body transformations. He always committed to changing his physique for roles that he did it twice for 1980’s Raging Bull.

First, De Niro put on muscle to play boxer Jake LaMotta in his prime, and once filming for that part was over, he took an extended vacation in Italy where he ate a lot of pasta to play an older, overweight LaMotta.

Director Martin Scorsese was so concerned by the actor’s laboured breathing that he put production on hold for De Niro’s health.

Demi Moore took with her an incredible level of discipline to preparate for G.I. Jane, in which she portrayed Lieutenant Jordan O’Neil, the (fictitious) first female Navy SEAL.

To achieve the physique of an elite special forces soldier, Moore undertook real SEAL training. She did a combination of cardio, strength training, and martial arts.

The actress continued training throughout production to maintain that chiseled look, waking up at 4am to get a few hours of working-out before filming.

2014 had Jake Gyllenhaal giving a critically acclaimed performance in Nightcrawler, a film which saw him lose a lot of weight.

The actor went through an extreme transformation for his role in boxing movie Southpaw, with Gyllenhaal putting on 15 pounds of pure muscle.

This required Gyllenhaal to spend six hours a day in the gym for six months straight, with dedication so intense that, according to the movie’s director Antoine Fuqua, contributed to his break up from Alyssa Miller.

There was pressure following Noomi Rapace’s acclaimed portrayal of literary anti-heroine Lisbeth Salander, so Rooney Mara transformed herself to play the role in the American remake of The Girl With the Dragon Tattoo.

Instead of prosthetic makeup, Mara got all the character’s signature piercings as detailed in Stieg Larsson’s books.

That included multiple earrings, an eyebrow bar, lip ring, two nose rings and more intimate piercings, even bleaching her eyebrows and having temporary tattoos applied.

Cage is also known for going method, with odd antics such as eating a live cockroach for Vampire’s Kiss and even moving an alcoholic into his trailer for Leaving Las Vegas.

But the actor’s most drastic preparation was for 1984’s Birdy, in which he played a young Vietnam War vet.

To get into the mindset of a wounded soldier, Cage willingly submitted for torture, having two of his teeth ripped out without the use of an anaesthetic.

Rapper-turned-actor Curtis ’50 Cent’ Jackson has had over 30 screen credits since his first role with 2005’s Get Rich or Die Tryin’.

Jackson was keen to prove his chops, dropping a staggering 54 pounds just to play a cancer-stricken football player in 2011’s All Things Fall Apart.

He is known for his bulky physique, so the gaunt, haggard appearance was truly shocking. Unfortunately for Jackson, the film was a flop.

2002’s The Pianist won universal acclaim and had Adrien Brody winning an Oscar, but the role nearly killed the actor.

The WWII-era drama casts Brody as a Jewish pianist, one who was struggling to survive in Nazi-occupied Warsaw.

He got into malnourished shape by going on a daily diet of two boiled eggs, a small piece of chicken, and some steamed vegetables. Brody lost 31 pounds in a short amount of time.

Brody later said that his “starvation diet” made him really ill, and that it really concerned his doctors.

Theron is known for her beauty, so her transformation into playing Aileen Wuornos was all the more impressive.

To become the real-life serial killer in 2003’s Monster, the actress put on 30 pounds by going on a diet of junk food.

Theron even fried her hair just to replicate Wuornos’ wispy locks.

Living on burgers and milkshakes might seem like a dream come true, but Theron says it made her miserable, confessing that she was “not that fun to be around” during production.

Chris Pratt rose to fame on TV’s Parks and Recreation, where he played the decidedly doughy Andy Dwyer.

But when he was cast as Peter Quill in the Marvel’s Guardians of the Galaxy, he underwent an incredible body transformation, shedding the calories and packing on serious lean mass.

When he was asked of his approach in changing his physique, Pratt said that he “started running and stopped eating.”

JK Simmons’ extreme body transformation for 2017’s Justice League is so impressive considering he was in his 60s when he did it.

Recruiting ex-Marine Aaron Williamson, the actor pulled off extreme discipline for his training and diet, achieving a physique younger men would envy.

Williamson later that Simmon’s new, healthy lifestyle meant he’d “never have to worry about health issues again.”

When Michael Chiklis’ role as Toni Scali on drama series The Commish came to an end, the actor decided to make major lifestyle changes.

He was overweight and that placed limitations on the roles he was offered, plus his wife was concerned about his health.

An opportunity to play a cop on The Shield provided him motivation, so Chiklis began training six days a week, and used a food delivery service to ensure he was eating portion controlled meals.

2000’s Cast Away has Tom Hanks being the sole survivor of a plane crash and finds himself stranded on an uninhabited island.

Before production started, Hanks abandoned his exercise regimen, letting go of his diet to achieve the “pudgy” physique of an average middle-aged man.

After shooting the first section of the film, production was stopped for a year. Hanks went on a strict diet to drop 55 pounds while growing out his hair and beard.

Jared Leto wasn’t the only one who lost weight for Dallas Buyers Club. Matthew McConaughey dropped 47 pounds in six months to play real life AIDS sufferer Ron Woodroof.

McConaughey’s diet included fish, tapioca pudding and “as much wine as I wanted to drink.”

He even abstained from exercise to achieve that suitably atrophied look.

The actor’s efforts paid off, with McConaughey taking home the Academy Award for Best Actor.

Before taking the role of beleaguered Private Pyle, Vincent D’Onofrio was a tall, athletic man. But his Full Metal Jacket role required him to put on 70 pounds of fat.

D’Onofrio described the process as extremely difficult, since his newfound weight made tasks like tying shoelaces difficult.

What he found hardest of all was the way people treated him. He remarked later, “it makes you realise all those typical things about beauty being deeper than what you would think.”

Hathaway has always been slim, but being in Les Misérables as struggling 19th century prostitute Fantine had the actress deciding that to properly convey her character’s struggle, she would really have to look like she was starving.

Hathaway lost ten pounds before filming, then another 15 during production just by eating just two pieces of oatmeal paste a day.

The drastic weight loss unnerved her doctors and left her feeling like she was constantly going to “collapse”.

He ticked off the hideously emaciated (The Machinist) and imposingly muscular (Batman), so Bale went for the trifecta of body transformation achievements by putting on an amazing 43 pounds of fat for his role in American Hustle.

The actor also deliberately developed a slouching posture so severe it led to a herniated disc in his spine.

The transformation was so successful that when Bale bumped into Robert De Niro on set, the veteran actor ended up asking who he was.

McConaughey proved his method acting credentials when he dropped weight for Dallas Buyers Club. But he proved that he can move the scales in the opposite direction as well, putting on serious fat to play overweight prospector Kenny Wells in 2016’s Gold.

McConaughey allowed himself to eat and drink whatever he wanted for six months.

Unlike some stars, McConaughey enjoyed this, saying that at the time his kids referred to him as “Captain Fun.”

Tom Hardy is no stranger to gaining pounds for a role, having previously bulked up to portray Charles Bronson.

But his role as Bane, the hulking nemesis of Batman in The Dark Knight Rises, required him to gain a staggering 30 pounds of muscle.

Hardy trained four times daily for months, and as a result of his hardcore training, the actor says he now has “joints that click that probably shouldn’t.”

Robert De Niro proved that crazy body transformations aren’t just for young actors when, aged 48, he got into amazing shape for 1991’s Cape Fear.

He played Max Cady, a revenge-obsessed ex-con. The actor got his body fat levels down to a staggering four percent in preparation for the role.

And just for reference, the body fat percentages of Olympic sprinters are somewhere between six and ten percent.

Norton was cast as a white supremacist in 1998’s American History X, so he knew he needed to add serious bulk to look more intimidating.

He dramatically upped his calorie intake, eating five meals a day with protein shakes in between, and going on a grueling weightlifting routine.

The actor gained 30 pounds of muscle in three months, leading Arnold Schwarzenegger, whom Norton got workout advice from, to ask if he was using steroids.

Pitt’s role as Tyler Durden in 1999’s Fight Club and the body he achieved has been voted the ‘perfect male physique’ in surveys.

The character is vocal about his disdain for gyms, so even Pitt relied exclusively on bodyweight exercises like push-ups, sit-ups, and pull-ups to achieve his look.

Unfortunately for other men determined to emulate the actor’s regimen in hopes of getting the same results, genetics played a major role here.

Portraying the greatest boxer to ever live is no easy feat, and Will Smith was more than determined to get it right.

The actor removed junk from his diet, spending six hours a day lifting weights and boxing, and going for runs in the snow wearing combat boots.

The reason he did this was because that’s what Muhammad Ali did.

Smith emulated every aspect of the boxer’s routine, from Ali’s diet to his training, and the results were pretty impressive.