Crazy moment Jack Nicholson 'pulled a gun' on Leonardo DiCaprio while filming

Leonardo DiCaprio didn’t need to do much acting when Departed co-star Jack Nicholson decided to spontaneously pull a gun on him during filming.

If you’re not acquainted with the 2006 Martin Scorsese film or you’re in need of a refresher, then strap in.

The Warner Bros. drama follows Boston cop Billy Costigan (DiCaprio) as he attempts to infiltrate Frank Costello’s (Nicholson) gang. Simultaneously, a criminal called Colin Sullivan (Matt Damon) is in the process of infiltrating the police.

In this high-stakes thriller, the moles must work against the lock to suss each other out. But not everything goes quite to plan.

The Departed is considered to be one of Scorsese’s most successful films to date — winning four Academy Awards including best picture and best director.

If you’re already a firm fan of The Departed then you know there’s one pivotal scene that is impossible to forget — ‘I smell a rat’.

Warner Bros.

In the iconic film scene, Costello sniffs glass and says, “I smell a rat” before pulling a gun on Costigan.

But did you know that Nicholson actually thrust the weapon into his co-star's face on a whim?

Apparently, Nicholson didn’t think the scene was ‘intense enough’ and decided to put his own spin on it by bringing a gun into the equation.

Speaking about the moment in the book Conversations With Scorsese by Richard Schickel, the director said: “The first thing Jack did was sniff the glass and say, ‘I smell a rat’… And then he pulled a gun on him.

“He didn’t tell me he had a gun. It was great… we took a lot out, but Leo’s reaction is real-time… I still get chills… It’s so real to me.”

Warner Bros.

At the time of the film’s release, DiCaprio himself touched on his raw reaction at a press conference.

He said: “There were a number of different scenes where I had no idea what was going to happen.

“One scene in particular, we did the scene one way, and I remember Jack speaking to Marty [Scorsese] 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.

“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.”

While it hasn’t been confirmed whether Nicholson pulled a real gun or a prop gun on DiCaprio, YouTube commenters have had their say on the matter.

After watching a YouTube shorts video regarding Nicholson vs DiCaprio, one user: “No chance an actor can just pull out a gun on a movie set without telling anyone… They’d get their insurance pulled so fast the whole operation would have to shut down.”

Another said, “You’re telling me Jack Nicholson flags Leonardo DiCaprio on purpose? That’s not cool.”

Another said that the gun Nicholson drew probably wasn’t real and explained: “guns [used on film sets] are often real or so close to real, DiCaprio might not be able to tell the difference anyway.”

Another said, “The ‘gun’ may have been impromptu but there’s no way it was real and loaded.”