Murphy, 47, was eating just one almond a day to shed the pounds to play gaunt scientist J Robert Oppenheimer, who famously survived on a diet of martinis and cigarettes.
Nicotine was a factor in Christian Bale’s extreme transformation for The Machinist, where he lost 62lbs — or about a third of his bodyweight — by surviving on a diet of an apple and black coffee a day and taking up smoking.
Charlize Theron went to the opposite extreme, however, after she gained 30lbs for her Oscar-winning role in Monster where she played a serial killer. She went even more extreme for a 2018 drama that saw her gain 50lbs by gorging on burgers, milkshakes and potato chips.
Below, DailyMail.com highlights five dramatic transformations celebrities have undergone for movies:
Christian Bale (pictured left in a 2002 film) is famous for his body transformations. One of the most severe was when he lost 62lbs in order to play insomniac Trevor Reznik (pictured right)
How Christian Bale lost 62lbs in four months to play emaciated insomniac in The Machinist: One apple, a tin of tuna and a cup of black coffee per day
One of the most dramatic body transformations in Hollywood history is that of Christian Bale. The actor lost 62lbs, or a third of his weight, for a psychological thriller.
When he was cast as machinist Trevor Reznik for the 2004 movie ‘The Machinist’ who was emaciated due to his insomnia, the star set himself a target of slashing his weight from 182lbs to just 120lbs.
The move worked, with reviewers commenting on the dramatic transformation at the time — and the performance earned him a nomination for Best Actor.
Mr Bale revealed he lost the weight in just four months after switching his normal diet for one apple, a tin of tuna and a black coffee every day. He also smoked cigarettes to help reduce his appetite.
This was a measly diet of less than 200 calories per day, well below the 2,500-calorie average recommended for men.
To help keep him on track, Bale said he would regularly sit around wearing headphones but not actually listen to anything so he could hear what was going on around him without being distracted.
He added to GQ: ‘Also, at the time I was engaged in a very filthy habit of smoking. So, I was rolling my own cigarettes and sitting there puffing away.’
Mr Bale has also previously swung the other way, bulking up to 220lbs for his role of Batman in The Dark Knight.
Years later, he gained weight again for his role in the 2018 film Vice. Mr Bale gained 40lbs to play the 46th US Vice President Dick Cheney.
But talking about his dramatic weight fluctuations in 2019, at the age of 45, he said he couldn’t keep transforming his body the way he had previously.
‘I just can’t keep doing it. I really can’t,’ he told GQ. ‘My mortality is staring me in the face.
‘I’ve become a little bit more boring now, because I’m older and I feel like if I keep doing what I’ve done in the past, I’m going to die. So, I’d prefer not to die.’
Curtis Jackson III, also known as 50 Cent, shaved off 54lbs in 2011 for the movie All Things Fall Apart where he played a football player with cancer (pictured right)
Curtis Jackson III (50 Cent): Ran on the treadmill for three hours a day to lose 54lbs for a cancer patient role
The movie star and rapper dropped a dramatic 54lbs — or a quarter of his weight — in an incredible transformation in 2011.
Curtis Jackson III, also known as 50 Cent, initially tipped the scales at 214lbs.
But in just nine weeks he dropped to 160lbs for his role as a cancer-stricken football player in the 2012 movie All Things Fall Apart.
The star achieved the transformation by only consuming liquids and running three hours a day on the treadmill.
Talking about his motivation for such a dramatic drop in pounds, Jackson said in an interview with Parade Magazine the aim was to best reflect the realities of cancer.
He revealed his best friend Charles Pringle, who lived across the street from him, suffered from cancer and had looked emaciated shortly before his death.
Describing his transformation, Jackson added: ‘The weight started coming off and my manager told me: “You better get yourself to a doctor!
‘I just didn’t want to go because I had to match the look in my mind.
‘I was so into what I was doing I wasn’t really concerned with that. I just kept looking at myself in the mirror feeling like I have to be smaller. I had to match.’
He added: ‘I had so much muscle on me that it was hard for me to lose definition even as I got lighter and slimmer.
‘I started running to suppress my appetite. Toward the end, it was really difficult. It was like, if I don’t get close enough to what my best friend looked like to me at that point before he passed, then I’m not doing the story any justice.’
Matthew McConaughey (pictured left in Texas this year) gained 47lbs in six months for his role as Kenny Wells (pictured right), a businessman who strikes gold in Indonesia in the 2017 film Gold
Matthew McConaughey: Ate pizza and cheeseburgers every night to gain 47lb in six months
One of the most shocking yo-yo body transformers in Hollywood is American actor Matthew McConaughey.
In 2013, after wrapping up filming for Magic Mike, in which he needed a muscular frame, the actor went on to shed all his added muscle and drop his weight for ‘Dallas Buyers Club’.
In this 2013 drama, he played Ron Woodruff — a cowboy in Texas who was stricken with AIDS.
To best reflect the character’s physique and illustrate the realities of the disease, Mr McConaughey lost 40lbs in five months — shifting from 188lbs to 135lbs.
This was achieved by eating fewer than 500 calories per day. He would have an egg white for breakfast, while lunch and dinner would be just five ounces of fish and a small side of vegetables.
The only snack he was allowed was tapioca pudding, which McConaughey admitted to eating with the smallest spoon possible to make it last longer.
Then in 2017, the actor — then aged 48 — went the other way and started putting on weight to play businessman Kenny Wells who was searching for gold in Indonesia.
He gained more than 47lbs in all for the role over the course of six months.
‘I was getting pretty damn fat as Kenny Wells,’ McConaughey told CNN at the time.
‘I was an all-star in my family, nicknamed “Captain Fun” during that time because I was yes to pizza night, every night, and it was cheeseburgers and beer.’
On this diet, the star enjoyed eating whatever he wanted whenever he wanted — which included plenty of pizza and cheeseburgers. He also quit exercise, deciding it was even too hard to walk up just one flight of stairs when an elevator was available.
Talking to Page Six, he said: ‘My favorite food is cheeseburgers, so I was eating cheeseburgers all the time.
‘I was trying out all these fast food restaurants that I’ve never had, or I’ve only had one time. Not that much sweets. Cheeseburgers and beer will do the trick.’
The father-of-three said the biggest challenge was trying to shed the weight afterward.
‘The hard part was getting down…I would go from 217 to 211, easy. Then 211 to 209. Crossing that 210 mark was really tough. Then [going from] 209 to 201: easy,’ he said.
Charlize Theron (pictured left before her weight transformation) gained 50lbs in three months to play a pregnant mother-of-three with postpartum depression in the 2017 movie Tully (right)
Charlize Theron after gaining 50lbs to play a pregnant mother-of-three: ‘My soul just felt really heavy’:
For the 2018 drama, Tully, Charlize Theron had to gain 50lbs in three months to play a pregnant mother-of-three with postpartum depression.
Ms Theron said the first three weeks of her weight-gain program were ‘easy’ but then became a ‘job’ to eat all the food required to gain the weight.
‘The first three weeks are always fun because you’re just like a kid in a candy store,’ she told the Associated Press.
‘So it was fun to go and have breakfast at In-N-Out and have two milkshakes.
‘And then, after three weeks, it’s not fun anymore. Like, all of a sudden, you’re done eating that amount and then it becomes a job.’
Describing the impact of gaining that much weight, she told PEOPLE: ‘I was very heavy, literally and figuratively.
‘My soul just felt really heavy on this film, and I was just really unhealthy and I threw my back out and couldn’t sleep and was lethargic.’
She finished filming just before Thanksgiving, saying this delayed her diet to lose the weight because of the holidays.
‘Then, when January came around, it was just like I could barely walk on a treadmill,’ she said.
‘My body just didn’t respond like it did the last time I did this. It took a year and a half for the weight to come off.’
Chris Pratt (pictured left in the series Parks and Recreation) traded in his dad bod for a more chiseled physique (picture right) for his role in Guardians of the Galaxy
Chris Pratt on his dramatic transformation for movie Guardians of the Galaxy: I lost 60lbs while eating 4,000 calories per day
Chris Pratt shot to fame in the comedy series Parks and Recreation, which premiered in 2009 and ran until 2015, where he played the goofy Andy Dwyer.
But within five years he traded in his dad bod for a more svelte and chiseled appearance in the 2014 movie Guardians of the Galaxy.
To prepare for the role, Mr Pratt lost 60lbs following a strict diet and exercise plan that included lifting weights, running, and swimming for four hours a day.
He was also consuming more than 4,000 calories per day, but said he was still losing weight because he was now eating the right types of foods.
‘I actually lost weight by eating more food, but eating the right food,’ he explained to PEOPLE magazine.
‘When I was done with the movie, my body hadn’t been in starvation mode. It wasn’t like I was triggered to just gorge myself and get really fat again.’
Mr Pratt has kept the physique, and in 2015 landed a role as park ranger Owen in Jurassic World — a nerd dream for the actor.
Cillian Murphy would not reveal how much weight he had lost to portray J Robert Oppenheimer, the scientist who developed the atomic bomb
Cillian Murphy on preparing to play the scientist who invented the atomic bomb: I survived on an almond a day
The most recent transformation demonstrated by a celebrity was Cillian Murphy for his role in the movie Oppenheimer.
In the thriller, the 47-year-old actor plays scientist J. Robert Oppenheimer as he works to develop the atomic bomb during World War II.
The scientist famously survived on a diet of martinis and cigarettes — rarely making time to eat.
And Mr Murphy went to extreme lengths to achieve the same appearance — consuming just one almond a day.
‘I was running on crazy energy; I went over a threshold to where I was not worrying about food or anything,’ he told The Guardian.
‘I was so in it, a state of hyper… hyper something, but it was good because the character was like that. He never ate.’
The weight loss was achieved over six months before shooting the film and Mr Murphy would not reveal how much weight he had lost or his finishing weight.