Something is compelling about seeing an actor utterly lose himself in a part. But for a select group of actors, “acting” simply won’t do—they become the character, breathing the role long after the cameras have stopped rolling. This is the high-risk, occasionally deadly realm of method acting, where actor and character become as one until it’s difficult to distinguish where one ends and the other begins. These are 10 of the most intense examples ever—counted down so we can leave the most intense ones for last.
10. Natalie Portman — Black Swan
Natalie Portman’s training for Black Swan was as rigorous as the film. She cross-trained under professional ballet teachers for hours a day, lost 20 pounds from her already pencil-thin body, and swam. She worked 16-hour days and “barely ate,” which exhausted her physically and emotionally. Portman afterwards revealed she inadvertently fell into method acting, describing it as the most difficult experience of her career.
9. Hilary Swank — Boys Don’t Cry & Million Dollar Baby
Swank’s commitment to realism has won her two Oscars. For Boys Don’t Cry, she spent a month living like a man—binding her chest, masculinizing her voice, and losing weight to look more like Brandon Teena. Years down the line, in Million Dollar Baby, she put on almost 20 pounds of muscle and worked out like a genuine boxer, even contracting a staph infection from a wound. She later commented that the Boys Don’t Cry role would now be suitable for a trans actor, but nobody questioned her dedication back then.
8. Christian Bale — The Machinist & Beyond
Few performers challenge their physiques as much as Christian Bale. To play The Machinist, he dropped nearly 70 pounds, living on a few calories more than coffee and apples, and reportedly sleeping only two hours a night. He’s also bulked up to superhero size for Batman Begins, then lost it again for The Fighter and American Hustle. Bale acknowledges that he ultimately had to stop such extreme fluctuations for health reasons.
7. Jamie Foxx — Ray
To embody Ray Charles, Jamie Foxx didn’t just study the legend—he lived in his skin. Foxx dropped 30 pounds and wore prosthetic eyelids glued shut for up to 14 hours a day. The darkness triggered panic attacks and claustrophobia until he adjusted. He likened the experience to serving “a jail sentence,” but the result was an Oscar-winning performance that felt eerily real.
6. Jared Leto — Dallas Buyers Club & Suicide Squad
Leto is infamous for taking it too far for the sake of character. In Dallas Buyers Club, he lost more than 30 pounds and remained in character as a trans woman both on and off the set. With Suicide Squad, his pranks as the Joker became Hollywood legend—sending offbeat gifts to co-stars, using a wheelchair on the set, and not breaking character. Love him or loathe him, he goes all the way.
5. Meryl Streep — The Devil Wears Prada
Meryl Streep is a chameleon, yet even she found method acting to be an emotional toll. Portraying Miranda Priestly, she remained chilly and remote from cast and crew, shunning small talk to keep up her character’s frightening presence. Streep afterwards described the method as making her miserable and depressed, and vowed never to work in that manner again, despite performing one of her most iconic performances.
4. Joaquin Phoenix — Joker
Phoenix lost 52 pounds to play Arthur Fleck, but the process extended far beyond the physical. The radical diet left him hyper-aware of motion, imbuing his Joker with an odd “fluidity” that informed the performance. He characterized the experience as mentally destabilizing, with an obsessive attention to each fraction of a pound shed.
3. Heath Ledger — The Dark Knight
Ledger’s Joker is both iconic and unsettling. He spent a month in a hotel room alone, writing notebooks full of the character’s thoughts and trying out different voices and mannerisms. On location, he encouraged Christian Bale to punch him during their interrogation scene. The intensity became exhausting, taking a toll on Ledger’s insomnia and mental endurance. His posthumous Oscar award is still a testament to the power of the performance.
2. Robert De Niro — Taxi Driver & Raging Bull
De Niro essentially authored the current rulebook for method acting. Before filming Taxi Driver, he acquired a genuine cab license and spent 12-hour days driving all around New York to immerse himself in the environment. For Raging Bull, he boxed for months, then suspended production to put on 60 pounds to portray Jake LaMotta’s later life. The realism in both performances remains unparalleled.
1. Daniel Day-Lewis — My Left Foot & Gangs of New York
If anyone were an ambassador of method acting, it would be Daniel Day-Lewis. For My Left Foot, he spent the whole shoot in a wheelchair, having crew members feed him. For Gangs of New York, he immersed himself off-camera in 19th-century living, eschewing modern amenities and even coming down with pneumonia because he refused to wear a modern coat. His dedication has landed him several Oscars and a reputation as the most intense actor of his time.
The Double-Edged Sword of Method Acting
These changes have provided us with some of film’s most enduring performances, but they also show the psychological and physical costs that accompany complete immersion. Genius results for some; high prices for others. Either way, these performers demonstrate that the difference between commitment and obsession is paper-thin—and the legacy they left behind is testament to how far they would take it.