Why did Vincent D'Onofrio gain so much weight?

Vincent D'Onofrio gained significant weight for his role as Private Leonard "Gomer Pyle" Lawrence in the film "Full Metal Jacket," directed by Stanley Kubrick. To authentically portray the character's transformation, he intentionally altered his physique, which included gaining around 70 pounds. His commitment to the role showcased his dedication to character immersion, reflecting the psychological and physical changes experienced by the character throughout the film.