10 Actors Who Conducted Insane Research For Iconic Movie Roles

4. Robert De Niro - Raging Bull (1980)

Raging Bull is one of many cinematic masterpieces brought to us by American legend Martin Scorsese, and a movie which also happens to feature what is probably Robert De Niro's greatest performance ever.

Based on the true story of heavyweight boxer Jake LaMotta (with all the inherent tragedy spilling out over the screen), De Niro conducted a hell of a lot of time-consuming research to prepare for the role that would eventually grant him an Oscar. Aside from gaining all the necessarily weight, De Niro would spent hours and hours every day training with professional boxing coaches.

To enhance the realism of his relationship with Joe Pesci within the movie, the pair opted to actually moving in with one another, as to reinforce the realistic nature of their on-screen friendship. De Niro didn't stop there: he continued his research by hanging out with LaMotta and his former girlfriend Vikki, as to learn as much as possible about their personalities and complicated history.

Trained by LaMotta, De Niro eventually discovered himself to be a pretty good boxer, and even entered a few fights as a middleweight (of which he won two out of three). LaMotta later said that De Niro had been one of the 20 best middleweight fighters he'd ever trained.