Adrien Brody gave up nearly all of his possessions to prep for his role in The Pianist.
In an interview with BBC, Brody claimed that he sold his car, moved out of his apartment, and gave up all materialistic things to move to England in prep for his role in The Pianist. He even ended his relationship with his then-girlfriend all to feel how his character Władysław Szpilman felt.
Brody went on to win awards for his performance, but many others have won for similar roles and managed not to pull a stunt like this.
Me too, Pal.