For her role as Aileen Wuornos in "Monster", Theron gained approximately 30 pounds and underwent a physical transformation that included altering her teeth and wearing prosthetics to darken her skin and create a more weathered appearance. She also changed her posture and gait.

To prepare for her role in "Aeon Flux", Theron underwent extensive physical training to develop a lean and athletic physique. She performed many of her own stunts in the film.

Charlize shaved her head to portray Imperator Furiosa in "Mad Max: Fury Road". This drastic change in appearance further emphasized the character's strength and resilience.

For her role in "Tully", Theron gained weight to portray a struggling mother. She later spoke about the challenges of losing the weight and the impact it had on her mental health.