1. Ben Kingsley – Mohandas Karamchand Gandhi in “Gandhi” (1982)

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Mohandas Gandhi (l) and Ben Kingsley in “Gandhi,”

The son of an Indian father and a British mother, Krishna Pandit Bhanji combined his father’s nickname (Benji) and his grandfather’s (King Clove) to come up with his now-famous stage name: Ben Kingsley. After working on the London stage for some 15 years, the young actor struck Oscar gold in only his second film, the sprawling biopic of India’s most famous activist leader. His performance as Gandhi earned Kingsley a place as one of the most celebrated actors of his generation; he was knighted by the British government in 2001.

2. Judi Dench – Queen Elizabeth I in “Shakespeare in Love” (1998)

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Judi Dench (l) in “Shakespeare in Love” and portrait of Queen Elizabeth I.

A year earlier, Dench had scored her first Academy Award nomination for playing another famous British queen, Victoria, in “Mrs. Brown.” As Queen Elizabeth I, she was famously on screen for only eight minutes, but stole every one of the scenes she was in. (It helped that those scenes came at key moments near the beginning, middle and end of the movie, and served as turning points in the action.) To her credit, Dench acknowledged the brevity of her role when she accepted her Oscar, saying: “I feel for eight minutes on the screen, I should only get a little bit of him.”

3. Nicole Kidman – Virginia Woolf in “The Hours” (2002)

Virginia Woolf, Nicole Kidman
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Virginia Woolf (l) and Nicole Kidman (r) in “The Hours.”

Nominated the previous year for her glamorous turn in “Moulin Rouge,” Kidman took on quite a different challenge with “The Hours.” Her marriage to Tom Cruise had recently ended amid intense publicity, and the actress pulled out of numerous projects around this time—but fortunately, she stuck with this one. To play Woolf, the left-handed actress learned how to write with her right hand and started smoking the writer’s preferred roll-your-own cigarettes. Sporting a frumpy makeup wig, heavy makeup and—most famously–a prosthetic nose, Kidman was nearly unrecognizable in the role, which won her a Best Actress statuette.

4. Cate Blanchett – Katharine Hepburn in “The Aviator” (2004)

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Cate Blanchett (l) in “The Aviator” and Katherine Hepburn.

Nominated for Best Actress back in 1999 for her fierce turn as Queen Elizabeth I in “Elizabeth,” Blanchett picked up her first Oscar for her supporting role in Martin Scorsese’s period drama about eccentric billionaire Howard Hughes. Played by Leonardo DiCaprio in the film, Hughes romanced a bevy of top Hollywood stars, including Ava Gardner and (you guessed it) Katharine Hepburn.

Scorsese had Blanchett watch all 15 of Hepburn’s earliest films on 35-mm prints; she also took tennis and golf lessons and enjoyed cold baths à la Hepburn (who died in 2003, just before filming on “The Aviator” began). The Aussie native also worked with a voice coach to mimic Hepburn’s distinctive upper-class New England accent and copied everything from her athletic walk to her red hair and freckles.

5. Forest Whitaker – Idi Amin in “The Last King of Scotland” (2006)

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Forest Whitaker (l) in “The Last King of Scotland” and Idi Amin (r).

Before taking on the role of the charismatic, brutal Ugandan dictator Idi Amin, Forest Whitaker researched extensively, watched documentaries and newsreel film of Amin and learned to speak Swahili and play the accordion. But that’s not all—the Texan-born actor of West African ancestry convinced Amin’s brother and sister to meet with him, and heard stories about the notorious general’s childhood firsthand. As Whitaker told the Telegraph: “It all helped me with figuring out the way he behaved and the way he thought, so that 24 hours a day, even in my dreams, I was totally consumed by the character of Idi Amin.”

6. Marion Cotillard – Edith Piaf in “La Vie en Rose” (2007)

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Edith Piaf (l) and Marion Cotillard (r) in “La Vie en Rose.”

For this biopic, in which she played France’s most famous chanteuse over the course of her turbulent life, Cotillard shaved her eyebrows and her hairline and endured five hours in makeup every day. She even developed a mode of contracting her muscles in order to make herself appear shorter; Piaf, who was only 4’ 11”, was also wasted by three serious car crashes and addictions to morphine and alcohol, among other health problems. Cotillard, who lip-synched in the film to Piaf’s real voice, won the only Oscar awarded to date for a French-speaking role.

In 2014, Cotillard told the Guardian that Piaf haunted her for months after the movie wrapped. “I did exorcisms with salt and fire. I traveled to Bora Bora to escape her. I went to Peru to Machu Picchu and did ancient shamanic ceremonies to cleanse myself after I eventually realized why I couldn’t let her go. She had been abandoned as a child. Her greatest fear was to be alone.”

7. Sean Penn – Harvey Milk in “Milk” (2008)

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Harvey Milk (l) and Sean Penn (r) in “Milk.”

In a press conference promoting Gus Van Sant’s film, Penn revealed that he prepared for the role by watching video footage of Milk, the San Francisco community organizer who was elected to the San Francisco Board of Supervisors in 1977, becoming one of the nation’s first openly gay elected officials. (The following year, he was murdered, along with Mayor George Moscone, by the troubled former supervisor Dan White.)

Penn said he kept the Oscar-winning documentary “The Times of Harvey Milk” (1984) and other video footage playing all day when he was preparing for the biopic of the gay rights icon. “If you see the documentary, the guy is a movie star…he is electric, a warm guy. You just reach and reach and reach, [but] never assume you’re going to get it all the way there.” Penn’s electric performance nabbed him his second Best Actor Oscar (the first was for 2003’s “Mystic River”).

8. Meryl Streep – Margaret Thatcher in “The Iron Lady” (2011)

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Meryl Streep (l) in “The Iron Lady” and Margaret Thatcher (r).

Meryl Streep seems to be able to rack up an Oscar nod just by appearing on screen—she has the most Academy Award nominations of any performer in history (19, including 15 for Best Actress)—but she has taken home the top acting prize only twice. After winning for “Sophie’s Choice” (1982), Streep had to wait 29 years before she got to brandish her second Best Actress statuette, for her portrayal of former British Prime Minister Margaret Thatcher in “The Iron Lady.” Though the film itself largely failed to impress many critics, Streep’s performance won nearly universal raves as a spot-on incarnation of the famously conservative prime minister from her early days in politics to her later life.

9. Daniel Day-Lewis – Abraham Lincoln in “Lincoln” (2012)

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Abraham Lincoln (l) and Daniel Day-Lewis (r) in “Lincoln.”

Day-Lewis, who grew up in England and Ireland, is known for going to the extreme to prepare for a role: Before his Oscar-winning portrayal of the severely paralyzed Irish author Christy Brown in 1989’s “My Left Foot,” the actor spent eight weeks living in a clinic for the disabled and learned to paint using only his foot. For “Lincoln,” Day-Lewis spent a year reading and studying the 16th president and worked tirelessly to cultivate Lincoln’s high-pitched voice and folksy speaking manner, as remembered in contemporary accounts.

To stay in character, the towering actor spoke in Lincoln’s voice between takes and even after filming wrapped. His Oscar win for “Lincoln” earned Day-Lewis membership in an elite club—of one—when he became the first performer ever to win three Academy Awards for Best Actor.

HISTORY Vault: Abraham Lincoln

A definitive biography of the 16th U.S. president, the man who led the country during its bloodiest war and greatest crisis.