Johnny Depp truly immersed himself in everything Hunter S. Thompson in preparation for his role as Raoul Duke (a character based on Thompson). He spent time with the writer, stayed in the basement (or the "dungeon") for about 4 months, and studied much of his work. The A-list actor copied notebooks, recovered conversations, and even wore some of his clothes from 1971. According to some reports, they hadn't been washed for 30 years! Thompson even allowed Depp to take his Chevy convertible dubbed the "Red Shark" to use in the film. Depp let the journalist shave his head to achieve a more authentic look. Benicia del Toro, who plays Dr. Gonzo (based on Thompson's friend Oscar Zeta Acosta), gained about 45 pounds in a little over 2 months before shooting began.

Will Smith, who plays Deadshot in the film, said in an interview with Beats Radio 1 that he has never actually met co-star Jared Leto. Smith revealed that the actor never broke out of character as the Joker. Leto confirmed with Empire that the many wild speculations of him sending disturbing gifts to fellow cast members -- including bullets to Smith and a live rat to Margot Robbie, who plays his leading lady (Harley Quinn) -- were true. "There was definitely a period of…detachment. I took a pretty deep dive. But this was a unique opportunity and I couldn’t imagine doing it another way. It was fun, playing those psychological games."

Martin Scorsese's Taxi Driver is not just considered one of the greats in the film world, it has also been lauded as greatly significant by the US Library of Congress. This is because the film highlights the possible effects of war on veterans in Robert De Niro's character, Travis Bickle. After an honorable discharge, Bickle, a former U.S. Marine, faces loneliness, paranoia, and insomnia. To combat his inability to sleep, he begins working as a taxi driver in New York City. De Niro prepared by acquiring a hack cab license and driving folks around for a month. Known for his history of method acting, De Niro also trained and gained weight for Raging Bull and reportedly has his teeth ground to look more like a criminal's in Cape Fear.

This film swept all five major awards, including Best Picture, at the 48th Academy Awards, and was selected for preservation in the National Film Registry in 1993. The plot focuses on McMurphy, played by Jack Nicholson, who pleads insanity in a case so that he could avoid time in prison. As a result, he is sent to a mental institution. Filmed at the real life Oregon State Mental Hospital, the cast worked closely with admitted patients there (who were included as extras) and stayed in character while on set.

When Val Kilmer was cast as Jim Morrison of The Doors, he was said to have learned how to play 50 of their songs. Only 15 of them were used in the film. Living members of the band commented that he had done such a good job on the vocals that they could not distinguish his from Morrison's. Kilmer also consulted with Paul Rothchild, who produced most of the band's albums and knew the members personally, on the minutest details: how Morrison would act in certain situations, like his behavior in a restaurant.

Daniel Day-Lewis is one decorated method actor; in 2012, Time named him the "World's Greatest Actor." We're taking you back to his role as Nathaniel Poe, or Hawkeye, in The Last of the Mohicans. He learned how to live off of the land and forest, track and skin animals, and how to build a canoe just like his character. He also kept his rifle with him at all times, including Christmas dinner, according to a New York Times article. To transform his body, he worked with fitness trainer Richard Smedley five times a week for six months. Afterwards, Day-Lewis lived in the woods of North Carolina for a month, where he stayed with experts on Native American culture.

"Saving Private Ryan was never meant to be thrilling, it was never meant to be an adventure," Steven Spielberg noted. "It was meant to be a recreation -- kind of a documentation -- the closest I could get to the experiences who fought there." So, he hired technical advisor Dale Dye, a retired captain who fought in Southeast Asia and the Middle East, to immerse the actors in a 10-day bootcamp. They spent 6 days in the field, where they ate canned food and slept on the floor. They also learned basic combat and survival moves while being yelled at in the pouring rain. Actor Tom Hanks knew that the experience would be unyielding, because he had worked with Dye before to prepare for Forrest Gump, but the others were unprepared. Spielberg hoped to build resentment between the cast and Matt Damon, who starred as the eponymous Private Ryan, and excepted him from the training.

Pollock was a personal project of actor-director Ed Harris, whose reading of the book "Jackson Pollock: An American Saga" sparked a desire to take the famous painter's story to the silver screen. Though Harris thought about the project for 10 years, filming occurred over a period of 50 days. After forty days, Harris scheduled a six-week layoff so that he could gain weight to mark changes over time. The devoted actor also tried his hand at Pollock's trademark drip style by creating his own studio, and invested some of his own money to make the film. "It was also very demanding and exhausting, but I didn't want anyone else to direct the film. I had worked on it long and hard and felt very intimate with it," Harris said in an interview. Hard work and passion paid off in this case. Ed Harris went on to receive an Academy Award nomination for Best Actor while Marcia Gay Harden, who played the artist's wife, took home the award for Best Supporting Actress.

Adrien Brody was first nominated for an Academy Award in 2003 for his portrayal of real-life Holocaust survivor Wladyslaw Szpilman in The Pianist, and he won. Brody was only 29 at the time, making him the youngest recipient for the award in the Best Actor category. The actor grew up in Queens, and Polish Jew Szpilman, who worked as a pianist and classical composer, lost his entire family in the war. He lived with the help of German captain Wilm Hosenfield. Brody decided to strip himself of all attachments -- his apartment, car, and phones -- before moving to Europe to liken himself to Szpilman. In the process, he dropped to 130 pounds, a staggering number for his 6' 1" silhouette. Director Roman Polanski also insisted he practice the piano four hours a day so that he would be able to play excerpts of Chopin.

Director Michael Mann said it best: "Tom Cruise is one of the most recognizable people on the planet. His voice is recognizable, his profile his recognizable. He can't put on a baseball hat and sunglasses and be in disguise and not be noticed." Cruise, however, was cast as a professional hitman (Vincent) in Collateral whose job depended on not being noticed. Mann then sent the A-list actor to deliver a package as a UPS deliveryman in Los Angeles's bustling Grand Central Market without being recognized. It seems simple enough, but deliverymen interact with customers in a number of ways -- finding the right person to deliver the package to, providing friendly greetings, and acquiring a signature. Committed to his role, Cruise successfully delivered the package and even sat down to have a conversation with a man -- and no one found out who he really was.

To prepare for the role of Trevor Reznik, an emaciated machinist, Christian Bale took to a daily diet of black coffee, canned tuna, and an apple. As a result, he dropped 62 pounds. At six feet tall, the actor weighed only 120 pounds. He also started smoking to curb his appetite. The film was received positively even by some of the toughest critics.

"To try and even touch what Jack Nicholson did in Tim Burton's world would be a crime," Heath Ledger said in one of his final interviews. And so, he set out to recreate his own Joker, one that captivated audiences inexplicably. For six weeks, Ledger isolated himself in a hotel room, where he documented ideas in a character diary -- inhumane things that the Joker would find funny, for example -- and experimented with voices. "It was awesome. It was the most fun I've had playing a character, hands down," Ledger later commented. The legendary actor suffered from insomnia and took prescription drugs, which, combined with exhaustion, reportedly contributed to his tragic death at 28, months before the film's official release.

In what he describes as a psychedelic movie with frightening images, Nicholas Cage painted on a voodoo style mask while on set for the second installation of Ghost Rider. He also wore black contact lenses and carried locating mystical objects with him, according to BBC. "I would gather things together to wear in my wardrobe, like a bit of Egyptian artifacts from a pyramid," he admitted. "Whether they work or not -- or you believe it or not -- if you're an actor and you give yourself over to it, it can stimulate your imagination and your psyche to believe you're the Ghost Rider."

Ashton Kutcher wrote about how he prepared for the role of Steve Jobs on Quora. In total, he spent about 3 months, starting by consuming content about the iconic figure. He watched documentaries and interviews before beginning to dissect the nuances of Jobs's behavior, from his accent to his walk. Kutcher wrote, "But I quickly found that, while learning 'how a person is' ultimately is the key, you have to learn 'why a person is.'" And so, he read books that Jobs read, such as "Autobiography of a Yogi" by Paramahansa Yogananda and "Diet Healing System by Arnold Ehretl"; adopted the same diet of grapes, carrot juice, and popcorn; and researched the artists and entrepreneurs he admired.

In an interview with Ellen DeGeneres, Shia LaBeouf said that he did not shower for four months to recreate an authentic experience for David Ayer's film, which focuses on a tank crew fighting in World War II. The actor admitted to inflicting a cut on his face and having one of his teeth removed. He described in an interview that these decisions were the smallest part of the job because they are simply "vanity stuff." He also went to say that they helped him believe in his role as a gunner. Ayer had the cast do some heavy sparring in between rehearsals to help achieve the family unit he had in mind, and even put them through a Navy SEAL boot camp.