Joe Pesci wasn't present at the 25th anniversary celebration of "Goodfellas" at the Tribeca Film Festival in April. However, that didn't keep him out of conversation during the Q&A that followed the screening of the film.

One of the most memorable scenes in "Goodfellas" occurs early on, when the audience is introduced to most of the crew at the Bamboo Lounge. Henry Hill (Ray Liotta) and Tommy DeVito (Pesci) get into a tense exchange in which Pesci asks "Funny how?"

Apparently, this scene was heavily improvised and based off of a story Pesci told at rehearsal.

Pesci and Liotta partially improvised this memorable scene during rehearsal. Warner Bros via YouTube "And Joe was telling me a story about what happened to him in Queens or wherever it was and he said to some guy ... the guy said something who happened to be a connected guy and he said 'Well ... you think I'm funny?'" Liotta told the audience.

A young Pesci was a waiter at a restaurant and told a mobster that he was funny. Needless to say, the wiseguy didn't take this compliment too well.

In the film's scene, DeVito seems to get offended after Hill calls him funny. "Am I a clown? Do I amuse you?" he asks.

The "funny how?" scene is one of the most quotable in the whole film. Warner Bros via YouTube While Pesci is not connected to the mob himself, he grew up around it, and this informed his experience in the film in the best way possible.

Scorsese liked this story so much that he allowed Pesci to bring it into the movie. However, he did not tell anyone outside of Pesci and Liotta that the scene would be improvised, because he wanted to see their genuine surprised reactions.

According to a making-of documentary, Scorsese decided to shoot this scene with only medium takes and no closeups, because he wanted to see everybody's genuine reactions.

Pesci's Tommy DeVito is known for being a loose cannon. Warner Bros via YouTube The distinction here between this scene and typical improvisation, is that it was improvised in rehearsal. Scorsese would then write it into the script.

"You don't improvise on camera when we're shooting," Pesci said in an interview during a making of documentary, "They all think that Marty [Scorsese] doesn't do anything, that he lets the actors say 'Okay, go ahead' and enjoys it. It's not true. It's crazy to think you can go in there and make a movie like that. It has to be structured."

Pesci won the Academy Award for best supporting actor for his role in "Goodfellas."

You can watch the (very NSFW) memorable clip below: