Between his axe-wielding performance in The Shining and his iteration of the villainous Joker in Batman, Jack Nicholson delivered his fair share of cinematic frights during his 55-year acting career. Sometimes, perhaps due to Nicholson’s penchant for method acting, he has even instilled fear in his fellow actors off-screen, including The Departed co-star Leonardo DiCaprio.

Marking one of DiCaprio’s early projects with habitual collaborator Martin Scorsese, 2006’s The Departed sees the director in his element at the helm of another mob-focused thriller. Nicholson is fantastic as mob leader Frank Costello, while DiCaprio plays Billy Costigan, who goes undercover in the mob.

According to DiCaprio, who revealed the story during a press conference at the time, Nicholson took the intensity of his character to extreme lengths. He was only on set for a short amount of time, but DiCaprio recalls shooting with him as “some of the most intense moments of the film” for him.

“There were a number of different scenes where I had no idea what was going to happen,” he recalled, “One scene in particular, we did the scene one way, and I remember Jack speaking to Marty because he said he didn’t feel that he was intimidating enough. It was one of the table scenes. It was one of the most memorable moments of my life as far as being an actor is concerned.”

At one point, Nicholson even pulled out a gun. DiCaprio continued to recall Nicholson’s unpredictable method acting, explaining, “I remember coming into the scene one way and then I came in the next day and the prop guy told me, ‘Well, be careful he’s got a fire extinguisher, a gun, some matches, and a bottle of whiskey.’”

Though intense, Nicholson’s performance only seemed to expand DiCaprio’s own performance and understanding of the scene, as he explained, “It gives you, I don’t want to say as an actor a sense of fear, but as a character a whole new dynamic. It completely altered and shifted the scene in a completely different direction.”

DiCaprio seemed particularly unnerved due to his character’s need to remain undercover. “We’re all professional actors, and we’re all playing roles,” he explained, “but for me playing this character of this guy that has to relay to the audience this constant 24-hour panic attack that I’m going through for my life, surrounded by people that would literally blow my head off if I gave them any indication of who I was, coupled with the fact that I’m sitting across the table from a homicidal maniac that will maybe light me on fire.”

Though it may have seemed unnerving and intense on set, DiCaprio and Nicholson both excelled in the film and delivered all-time great performances. Revisit one of their most intense scenes together below.