A good actor can really transport you, making you believe in whatever they're selling, whether that's superhero antics or whisking you to a world gone by.
But there are times when an actor's physical transformation can almost be *too* convincing, and has audiences at home doubting if it really is their favourite star on screen.
We've picked some of the craziest transformations celebrities have gone through for a role...
The craziest transformations celebrities underwent for a role
Charlize Theron - Monster
For the 2003 movie, Monster, glamorous screen goddess Charlize Theron transformed into the serial killer, Aileen Wuornos.
Aileen was a prostitute who murdered seven of her male clients between 1989 and 1990 and was eventually executed in 2002.
For the role, Charlize gained 30 pounds, shaved her eyebrows, and wore prosthetic teeth - as well as exploring the darker side of things mentally, capturing Aileen's borderline personality disorder. The transformation was worth it - Charlize took home the Oscar for Best Actress at the 2004 Academy Awards, beating out the likes of Diane Keaton and Naomi Watts.
Jennifer Aniston - Cake
Jennifer Aniston's best looks over the years have cemented her in our minds as the sunny, stylish and quintessential Girl Next Door, which is why her 2014 transformation for the movie, Cake, was a huge surprise.
Jennifer played the role of a woman struggling with chronic physical pain on top of the mental anguish of losing her son in a car accident. Capturing the raw feel of her character, Jennifer went without makeup and styling for the movie.
The radical departure from Jennifer Aniston's usual roles earned her a Best Actress nomination at both the Golden Globe Awards and the Screen Actors Guild Awards.
Renee Zellweger - Bridget Jones' Diary
Bridget Jones was the iconic heroine created by British writer Helen Fielding. Capturing the voice of single women in the 90s, Bridget was quintessentially British and someone to root for - a bit obsessed with her weight, a lot unlucky in love and often finding herself doing something unintentionally embarrassing.
So when it was revealed the book would be first made into a film back in 2001, the casting choice surprised a lot of fans. Renee Zellweger - not British, incredibly glamorous - would step into the big shoes (and the big knickers).
Going all out, Renee has repeatedly stated that she gained around 30 pounds for the role, doing it all again for the second film in the series, Bridget Jones: The Edge of Reason.
Anne Hathaway - Les Miserables
Anne Hathaway silenced any critics with her gritty and moving transformation for the 2012 movie adaptation of Les Misérables.
Playing the role of Fantine, a single mother who loses her job and ends up as a prostitute, Anne reportedly lost up to 25 pounds to play Fantine at her lowest. But the most shocking transformation was sheering her trademark long, brunette locks.
In the musical, Fantine sells her hair for money. To give that sacrifice some real power on screen, Anne actually allowed her real hair to be cut during the scene.
Per Screen Rant, Anne described the scene on Live! with Kelly, stating, "I was inconsolable and when we cut it, we did the first part with an actress, and she cut the front of my hair, and then we had to take a 20-minute break while my hair guy Paul had to put on her costume, which was a dress. And I just had to sit there for 20 minutes just like being half bald and that was pretty intense."
Matthew McConaughey - Dallas Buyers Club
Matthew McConaughey was best known for his hunky, romcom heroes until he well and truly transformed this image with his Oscar-winning turn in 2013's Dallas Buyers Club.
McConaughey took on the role of real-life AIDS patient Ron Woodroof, who challenged the US government to bring unapproved medication to others dealing with the condition.
Per the BBC, McConaughey lost almost 50 pounds for the role - but he did so as healthily as possible.
"I met with a nutritionist. I gave myself four months to lose the weight. I had my programmed meals, lost 3.5lb a week - like clockwork - and got down to my desired weight, which turned out to be 47lb lighter."
Nicole Kidman - The Hours
Nicole Kidman's best looks showcase why she's remained a style icon for years - and arguably one of the last bona fide movie stars.
However, the glamorous Oscar winner was almost unrecognisable for her turn in 2002's The Hours. Playing real-life writer Virginia Woolf, Nicole's blonde tresses were replaced with a mousy brown wig and a prosthetic nose completely transformed her appearance.
Different reports state that Nicole took around three hours getting made up every day while filming.
Rooney Mara - The Girl with the Dragon Tattoo
In 2011, Rooney Mara starred as Lisbeth Salander, or the Girl with the Dragon Tattoo, in the film of the same.
Per CBS News, Mara described the transformation as being "very intense" and it required her to bleach her eyebrows (something which became a bit of a trend amongst the fashion crowd between 2023 and 2024!), give her hair a choppy, rocker style, and pierce her lip, brow, nose and even nipple.
Christian Bale - Vice
Christian Bale is no stranger to transforming for a role - bulking up to play Batman in the Dark Knight series and becoming the uber-stylish but uber-unhinged psychopath in American Psycho.
However, in 2018, he might have made his craziest makeover ever - becoming a doppelganger of former Vice President Dick Cheney. Starring in Vice alongside Sam Rockwell as George W. Bush, Amy Adams as Lynne Cheney and Steve Carell as Donald Rumsfeld, Christian Bale put on over 40 pounds to play the former VP.
Demi Moore - G.I. Jane
In 1997, Demi Moore went from raven-haired red carpet icon to the rough-and-tough G.I. Jane.
For the role, the Ghost star buzzed off her trademark jet-black locks and put herself through intense Navy SEALs training, which, per Fandom Wire, included intense five-mile runs and brutal regimes.
Tom Cruise - Tropic Thunder
One of the major stars of the box office blockbuster, Tom Cruise famously puts himself through *a lot* for his films - whether it's scaling the world's tallest building for Mission Impossible or literally jumping out of planes.
But one of his most remarkable transformations came from an unlikely cameo appearance in the comedy, Tropic Thunder. Donning comically fat hands, a bald head and extra weight, Tom played Les Grossman, a foul-mouthed studio executive.
John Travolta - Hairspray
After stealing hearts around the world with his appearance in 1978's iconic musical Grease, John Travolta announced his heroic return to the genre with 2007's Hairspray. Only this time, he was more Sandy than Danny...
John Travolta's epic transformation for Hairspray saw him play the role of Edna Turnblad, the larger-than-life mother of protagonist, Tracy Turnblad.
Getting into the 30-pound body suit and undergoing the hair styling and makeup took around four hours, according to several reports at the time.
Charlize Theron - Bombshell
Charlize Theron is a recognisable face the world over, starring in films like Mad Max: Fury Road and being the ambassador for Dior for many years. But in 2019, she swapped her face for another famous one - Megyn Kelly.
Joining forces with Nicole Kidman and Margot Robbie, Charlize portrayed Megyn Kelly during the real-life scandal which saw Fox News titan Roger Ailes brought down for his years of sexual harassment.
Kazu Hiro, a Hollywood prosthetist, was largely behind the epic transformation. He would spend three hours a day applying the pieces that turned the Oscar winner into the controversial news anchor, and an interview with Elle delves into the details of how he used 3D scans to create eyelid moulds, chin pieces and much more.
Sarah Paulson - Impeachment: American Crime Story
American Horror Story actress Sarah Paulson spent hours a day transforming into the real-life Linda Tripp in 2021's Impeachment: American Crime Story.
Linda Tripp was an American civil servant who secretly recorded Monica Lewinsky's phone calls about her relationship with Bill Clinton.
Rufus Sewell - Scoop
The Holiday star Rufus Sewell caused many people to do a double-take when he transformed into a dead ringer for Prince Andrew in 2024.
Sewell transformed into the controversial Prince for Netflix's film, Scoop, which focused on the now infamous Newsnight interview between Andrew and Emily Maitlis.
Per Huffington Post, prosthetics designer Kristyan Mallett explained that the process began with an image of Rufus’ face being "overlaid" with Andrew’s, and then needing the application of "eye bags", a "nose piece" and an artificial forehead.
Emma Thompson - Nanny McPhee
Dame Emma Thompson checked her ego at the door for 2005's Nanny McPhee and the 2010 sequel, Nanny McPhee Returns, swapping the glitz and glamour of usual Hollywood makeup to become the warts-and-all titular nanny.
The dramatic transformation included an oversized, bulbous nose, snaggle teeth, a unibrow and more.
Calista Flockhart - Feud: Capote vs the Swans
Calista Flockhart has always kept her style more laidback and California chill, but for 2024's Feud: Capote vs The Swans, she transformed into the real-life society doyenne, Lee Radziwill.
Lee - sister to Jacqueline Kennedy Onassis - was the embodiment of New York High Society. Of the glamour she brought to the role, Calista told People she channelled a bygone era.
"I was thinking a lot about how I came to New York in 1988, 1989, and people still dressed up to go to the theatre... And I remember very quickly, that changed. I remember thinking, oh, I can just wear anything I want now to go to a play. There was a sadness to that - and also a relief. It was kind of the end of an era that these women experienced at the end of the show."
Renee Zellweger - The Thing About Pam
In 2022's The Thing About Pam, Oscar-winning actress Renee Zellweger was practically unrecognisable due to her transformation into convicted killer Pamela Hupp.
To become Hupp, who was charged in July 2021 for a stranger-than-fiction murder and cover-up plot, Zellweger had to wear a number of prosthetics which took around eighty minutes to apply, and then the look needed another two to four hours to perfect.
Marion Cotillard - La Vie en Rose
It took Marion Cotillard five hours a day to physically embody the role of legendary French singer, Edith Piaf - and reportedly it took another hour to take it all off at the end of the day.
But it was all worth it. Marion took home the Oscar for Best Actress after channelling Piaf in 2007's La Vie en Rose. It marked the first time an Oscar had been given for a French-language role.
Emma Stone - Battle of the Sexes
In 2017, Emma Stone became tennis pioneer Billie Jean King for Battle of the Sexes, a movie based on the real-life tennis match between Billie Jean and Bobby Riggs.
"Billie Jean King didn’t wear a lot of makeup," explained Torsten Witte, makeup artist for the movie.
She told Hollywood Reporter, "Tan, tan lines, freckles, eyebrow shapes, shading and scars was more the direction we needed to take Emma Stone to her character as Billie Jean King.” So the system involved a spray tan, self-tanner and some makeup."
Michael Fassbender - Hunger
In the 2008 film, Hunger, Michael Fassbender played Provisional Irish Republican Army (IRA) member, Bobby Sands, who led the second IRA hunger strike in 1981.
According to The Guardian, in preparation for the role, he shed 35 pounds. To achieve the tough makeover, Fassbender was reduced to eating a "very small tin of sardines every evening".
Hilary Swank - Million Dollar Baby
While Hilary Swank didn't have to sit through hours of prosthetics or facial transformations for the 2004 film, Million Dollar Baby, she put herself through an exhausting physical transformation.
She told Movie Web, "My training was two and a half hours of boxing and approximately an hour and a half to two hours lifting weights every day, six days a week."
"I gained 19 pounds of muscle... in order to do that, I had to eat 210 grams of protein a day. Now, your body can only assimilate so much protein, so I had to eat every hour and a half. So with a meal, I would drink my egg whites."
Sounds... pleasant. But for her efforts, Swank walked away with the Academy Award for Best Actress.
Christian Bale - The Machinist
Method acting might seem like an extreme approach to many, but even the most ardent supporters of the style were shocked at Christian Bale's dangerous approach to the 2004 film, The Machinist.
To play the role of an insomniac, Bale underwent a disturbing transformation including a 60-pound weight loss. He told Men's Journal he did so by "smoking cigarettes and drinking whisky".
A diet one should never try.
Sofia Vergara - Griselda
Modern Family's Sofia Vergara is known for her bombshell looks and lively sense of humour. But she underwent one of the most shocking transformations in 2024 to become the real-life Griselda Blanco, known as the Cocaine Godmother.
Sofia's transformation included five wigs and numerous prosthetics, including a fake nose and fake teeth to reflect the different periods.
Tilda Swinton - Suspiria
Tilda Swinton played three different characters in the 2018 horror remake, Suspiria.
While each one required some form of transformation, none was quite as shocking as her epic makeover into Dr Jozef Klemperer... an elderly man.
Per Deadline, she had to thicken her jaw and neck, and was completely covered in several prosthetic sections, with a silicone tubular neck, cheeks, chin, top lip, nose, forehead, ears, back of the head, hands, fingernails, a wig, and body padding.
Natalie Portman - Black Swan
Darren Aronofsky's dark psychodrama, Black Swan, follows the life of a ballerina so desperate for perfection she veers into madness.
Fittingly, then, Natalie Portman pushed herself to extremes to transform for the role, reportedly losing 20 pounds and putting herself through intense hours of exercise daily to truly capture the mindset of a leading ballerina.
Elizabeth Taylor - Who's Afraid of Virginia Woolf?
In 1966, Elizabeth Taylor remained one of the most glamorous stars of Hollywood's Golden Age. That is why her transformation for the movie, Who's Afraid of Virginia Woolf?, proved so shocking.
Gone was the dazzling star, famed for her love of diamonds and those trademark violet eyes, and instead, Elizabeth wanted to really do the role justice, gaining 30 pounds of weight, choosing less flattering fashion and a streaked grey wig.
She played the role of a grieving, acidic woman who is at war with her alcoholic husband, played by her real-life husband at the time, Richard Burton.
Jared Leto - House of Gucci
2021's House of Gucci promised to be one of the most stylish movies ever made, tracing the evolution of the fashion house and starring the likes of Lady GaGa and Salma Hayek.
However, one of the most shocking aspects of the film was the radical transformation of Jared Leto into Paolo Gucci. The makeover was laborious, and prosthetics designer Göran Lundström told Variety, "It took us an hour and a half just to cover his hair."
Emma Thompson - Matilda
All those hours turning into Nanny McPhee must have given Emma Thompson the taste for radical transformations, as the Oscar winner underwent another dramatic onscreen transformation to play Miss Trunchbull, the sadistic principal in Netflix's film adaptation of the Matilda musical.
The makeover took three hours in the make-up chair each day.
Cate Blanchett - I'm Not There
2007's I’m Not There is the unconventional biographical film about Bob Dylan. In sticking with unconventional choices, Oscar-winning actress Cate Blanchett played a version of the musical icon.
She was one of six actors who played him. As for how she got into the spirit of the transformation? A sock.
She said, "A friend of mine who’s a make-up artist said to me a few days into the shoot: ‘Put a sock down your pants!' I said: ‘What?!’ She said: ‘You’re on the bed, put a sock down your pants,’ and I said, ‘Oh, OK’ and I did! And I didn’t look back. It absolutely helped."
Margot Robbie - Mary Queen of Scots
Margot Robbie has a knack for playing women with iconic aesthetics - from Barbie's trademark blonde to Queen Elizabeth I's ghostly-white face and red hair.
For the 2018 film, Mary Queen of Scots, Margot fully embraced the look and became nearly unrecognisable.
Trivia: the actual reason Elizabeth wore the shocking makeup was because of a case of smallpox. She nearly died from the disease and her skin was scarred from the illness, so she covered the pockmarks with heavy white makeup made of white lead and vinegar, which slowly poisoned her over time.
Lily James - Pam & Tommy
When the first look for 2022's Pam & Tommy was released, fans on social media pretty much had the same reaction - wondering if they were actually looking at images of Pamela Anderson or if actress Lily James really had pulled off the most incredible transformation.
As it turns out, the Mamma Mia! Here We Go Again star really had become unrecognisable, taking on an eerily spot-on resemblance for the Baywatch icon.
Lily reportedly spent around four hours each day to morph into Pammy, and told Vanity Fair, "It’s just insane to look in a mirror and really not see yourself anymore... It just meant that I felt so much braver. I had less of my own self-inflicted boundaries of what I am and how I perceived myself. And this was just like, all gloves are off. I could just be anything."
Jessica Chastain - The Eyes of Tammy Faye
An unmistakable beauty with Old Hollywood looks and a glittering career, Jessica Chastain completely transformed and disappeared into her Oscar-winning role as televangelist Tammy Faye Bakker in 2022.
For The Eyes of Tammy Faye, the efforts taken to transform included "a full neck wrap and larger cheeks to convey weight gain" and "'larger cheeks and chin, [and] lip prosthetics to age her."
Overall, per the Los Angeles Times, she spent up to 7 and a half hours in the makeup chair per day.
