Content warning: this post mentions suicide and contains descriptions that may be triggering for those who have experienced an eating disorder.
Sometimes, an actor's commitment to playing a role is something to be admired, but occasionally they go a little too far for whatever reason.
Here are 18 times actors permanently altered or damaged their bodies in order to play a movie or TV role to the best of their ability.
1. JoJo Siwa has talked about the hair loss she experienced as a result of appearing on Dance Moms. The dancer and singer appeared on the show from 2014 until 2016, and during that time developed a "stress rash" which she would "pick at".
"I damaged every single hair follicle that was there" JoJo said while showing her bald spot in a recent TikTok. "So now I'm carrying her love with me", she continued.
2. To play Bane in The Dark Knight Rises, Tom Hardy trained four times a day to add over 30 pounds of muscle to his body, which left him with "joints that click that probably shouldn't".
The actor spoke to The Daily Beast and said that he had "probably damaged [his] body too much" by getting in shape for the role, as well as for Warrior.
3. For a few of his films, Christian Bale has lost weight and gained weight in quick succession, causing him feel like his "mortality is staring [him] in the face."
Christian dropped down to just 54 kilograms to play an insomniac in The Machinist. In the same year, he gained 45 kilograms to play Batman. He actually ended up gaining so much muscle that he didn't fit into The Batsuit, so he had to slim down again.
4. Last year, Jessica Chastain admitted that playing televangelist Tammy Faye Bakker — who was famous for how much makeup she wore — had left her skin feeling stretched out.
"I think for sure I've done some permanent damage to my skin", she told LA Times. The 45-year-old Oscar winner recounted how she spent up to seven and a half hours in the makeup chair, and felt like the heavy layers of makeup had aged her prematurely.
5. During the filming of Deadpool 2, Zazie Beetz got burned by a stray shell casing during a particularly tricky shootout scene, an accident that left a scar on her chest.
Although she trained for two months — including cardio, weight training, and mixed martial arts — Zazie felt she was hampered by her leather bodysuit costume, which she described as "wildly impractical".
6. Ariana Grande once revealed that years of bleaching her hair and dying it red for her roles on Victorious and Sam & Cat left her hair looking "absolutely ratchet and absurd" when down — hence the high pony.
The singer and actor shared that she tried wigs and weaves in a Facebook post, but they looked "ridiculous". She went on to explain that wearing her hair in a ponytail with extensions made her feel more "comfortable".
7. Similarly, Zendaya experienced awful hair damage after starring in Shake It Up. The Spider-Man star revealed that appearing on the show ruined her hair, and that she wasn't sure whether it would ever return to normal.
"Heat-styling destroyed my hair", she told People Magazine. "I was only 14 years old, and I didn't know how to protect my hair, so it took over two years to grow it back, which really sucked!"
8. On the set of Operation Condor, Jackie Chan performed a stunt that resulted in him needing brain surgery. In an interview with Parade, he described how a stunt — something Jackie is known for doing himself — led to a permanent injury.
"It was actually just a simple stunt, jumping from a slope. But I was seriously injured and had a surgery to my brain... I still have a metal plate in my head and can feel the indentation from the impact."
9. Jared Leto has expressed that gaining over 30 kilograms for the indie film Chapter 27 gave him gout and left him in a wheelchair as he could no longer walk to set.
"It was so painful", he told LA Times. "My body was in shock from the amount of weight I gained. It took about a year to get back to a place that felt semi-normal. I don't know if I'll ever be back to the place I was physically."
10. Back in 2005, George Clooney suffered a severe back injury on the set of Syriana that resulted in him "blowing spinal fluid out his nose".
In an interview with Rolling Stone, the actor recounted how serious the injury was and how hopeless it made him feel, revealing that he even thought about ending his life.
11. Martial arts queen Michelle Yeoh told USA Today that she once tore the ACL in her knee after a "mishap landing" on the set of Crouching Tiger, Hidden Dragon. She received months of physical therapy, but feels like her injury has permanently changed her.
"I was doing a forward jump kick that I've done thousands of times but I had a mishap landing... My knee just gave out." Yeoh remembered wanting to go on, but her "leg kept swinging right."
12. Angelina Jolie picked up a permanent scar on her face during the filming of Salt back in 2010. The movie required her to fight and jump off of buildings, and during one scene she incurred a minor injury with lasting effects.
Allegedly, it was a "ridiculously" easy scene in which Angelina had to dive through a door while firing a gun, but she ended up running into a piece of set. "I was bleeding and I have a little scar now", the actor revealed at a Comic-Con festival in San Diego.
13. Daniel Craig has been through it playing 007! The actor relishes doing his own stunts, and revealed that during the filming of Casino Royale he smashed out his two front teeth. Years later, during Quantum of Solace, he also lost the tip of one of his fingers!
Daniel lost his teeth during a fight scene with some extras in Prague; he was quickly visited by a dentist who replaced them. His finger was sliced on the set of his next Bond film, which lead to an immediate break in shooting while the crew searched for the top of the actor's digit.
14. The Wizard Of Oz lives in infamy for the way the cast was maltreated on set. Soon after filming began, Buddy Ebsen — the original actor for the Tin Man — was hospitalised with serious breathing difficulties thanks to the aluminum dust present in the makeup he wore.
Buddy had to bow out of the role and was replaced by Jack Haley, on whom they used a safer aluminum paste — although it still gave him an eye infection.
15. Also, Ray Bolger — who played the Scarecrow in The Wizard Of Oz — ended up with permanent lines on his face caused by the rubber prosthetic mask that was glued onto him every morning before filming.
Allegedly, the mask Ray wore wasn't porous, meaning he couldn't sweat and at times felt like he was "suffocating". When he finally removed the mask for good, the actor had scars around his mouth and chin which lasted for over a year.
16. On the set of the 1996 film Star Trek: First Contact, a stunt involving Alfre Woodard went awry when an explosion knocked her and her costar, James Cromwell, off their feet. Alfre injured her arm and still bears the scars today!
"There was huge explosion that we practised for about five hours", the actor told Collider. "When it happened, the explosion was so intense it just knocked us off our butts... My arms were bleeding and all the skin was gone... That's the memory that I have of First Contact."
17. This was more of an accident than him "over-committing" or being directed poorly, but Bruce Willis ended up losing two thirds of his hearing in his left ear during the making of Die Hard.
Bruce's daughter Rumer Willis has even said that her actor father can seem rude when appearing on chat shows, but in fact he's actually struggling to hear questions most of the time!
18. And finally, Tom Hanks believes his Type 2 diabetes diagnosis could partly be a result of him gaining weight and slimming down over and over again for roles, including for Castaway, Philadelphia, and A League Of Their Own.
The Oscar-winning actor once spoke at a press conference, admitting that he had a genetic predisposition towards diabetes, but also that he felt gaining and losing weight "may have had something to do with [it] because you eat so much bad food and you don't get any exercise when you're heavy."
Dial 988 in the US to reach the National Suicide Prevention Lifeline. The Trevor Project, which provides help and suicide-prevention resources for LGBTQ youth, is 1-866-488-7386. Find other international suicide helplines at Befrienders Worldwide (befrienders.org).
If you're dealing with an eating disorder and need someone to talk to, the National Centre for Eating Disorders Helpline is 0845 838 2040 and you can find Beat Eating Disorder's one-to-one web chat here. You can find out more about Eating Disorder Awareness Week here.