Jack Nicholson improvised one of the best scenes in cast of The Departed includes Matt Damon, Mark Wahlberg, Vera Farmiga, Alex Baldwin, and Martin Sheen.

Billy infiltrating Costello's gang and Colin infiltrating the police department leads to Jack Nicholson's best roles, and this becomes evident in one particular scene during which he's trying to scare DiCaprio's character. While talking at a bar during a scene in The Departed, Nicholson actually surprised DiCaprio by pulling out a gun and pointing it at him.

Nicholson Pulling A Gun At DiCaprio Was Not In The Script (& DiCaprio Didn’t Know About It)

Nicholson Surprised DiCaprio With A Pistol While Filming The Departed

According to Variety, before filming a scene in The Departed in which Costello is trying to intimidate Billy, Nicholson asked the prop master to hide a gun on the set. Since the script for this scene never indicated that Costello was going to pull out a gun, neither DiCaprio nor director Martin Scorsese expected Nicholson to wield a pistol. However, while talking to Billy about a potential mole in his organization, Costello pulls out the pistol and points it at both himself and Billy.

There was no reason for Nicholson to pull out a gun during this scene, as his character wasn't going to use it. However, openly wielding the gun made Nicholson's character so much more menacing, and actually makes for one of the best scenes in the movie. This improvised moment actually ended up making the final cut of The Departed, and it is easy to see how surprised DiCaprio actually was that Nicholson pulled a pistol out.

Did Costello Know Costigan Was A Rat During Their Conversation At The Bar?

Billy Fools Costello In The Departed

Before this scene, Billy was questioned about being a potential rat. However, Billy utilizes his police training and plays it cool under pressure. Throughout the film, he manages to convince Costello that he is loyal to him. Therefore, even though Costello knows that there is a rat in his organization, he doesn't necessarily think it's Billy during this scene. This is why he never actually intends to use the gun while talking to Billy in the bar. More than likely, he just wants to scare Billy a little bit.

Costello not figuring out that Billy is the rat is actually a common criticism of The Departed. In the film, Costello is aware that Billy was supposedly kicked out of the police academy. This should have been a much bigger red flag for Costello than it appeared to be. However, Costello seems to enjoy having Billy around, and therefore doesn't think he's the rat at this point in The Departed.

Source: Variety