Jennifer Lopez As Selena Quintanilla-Pérez – Selena (1997)

Playing Selena was perhaps Jennifer Lopez’s biggest break, and the most challenging. There were about 22,000 girls who auditioned for the part, and it went to Lopez. Selena’s family approved of the selection, but it was met with opposition from fans. To prepare herself for the role, Lopez bonded with Selena’s family. She moved in with the singer’s sister Suzette Quintanilla. Selena’s dance moves were also quite a challenge for Lopez. But through it all, the movie was a success, and Lopez’s portrayal of Selena was one of the most compelling in Hollywood’s history.

Charlize Theron As Aileen Wuornos – Monster (2003)

Charlize Theron often played glamorous roles. But for the movie Monster, she had to undergo incredible physical transformations that are a far cry from the roles she was used to. She had to gain 30 pounds and wear prosthetic teeth for her role as Aileen Wuornos, the real-life serial killer. She also watched lots of footage of Wuornos, which, to her admission, she was lucky to have enough of. She would then spend a lot of time in front of the mirror to mimic Wuornos and try to get comfortable with some of the things the serial killer would constantly do as captured in those films. In the end, Theron’s sacrifices and hard work paid off. The film was a critical success, won her a Golden Globe and an Oscar nomination.