Robert De Niro slammed Slack messaging application Chief Executive Officer and Flickr Co-founder Stewart Butterfield at Wall Street Journal's "The 2015 Innovator Awards" on Nov. 4 and dropped the F* Bomb on him in front of other celebrities, supermodels and awardees in attendance. De Niro's very short and very puzzling message to Butterfield reveals that he thought the Tech CEO was condescending towards actors.

The cause of the unexpected incident still remains a mystery to most since no one is sure which part of Butterfield's speech and joking remarks set the Oscar winning actor off. In his speech, Butterfield joked about being far from San Francisco as he scanned the room full of celebrities and that he was receiving a nerd award. He also pointed at De Niro and mentioned that he watched the veteran actor's film "The Godfather II" on the plane.

"Whoever the last speaker was . . . I thought you were a bit condescending to us actors . . . celebrities. I'm gonna go on record with you just to say that. And I don't give a f - - k who you are," De Niro said on stage.

Anything could have caused De Niro to be upset, but it could also be a misunderstanding since the actor specifically pointed out Butterfield's condescending attitude in his speech, which none could sense since Butterfield reportedly spoke in a joking manner.

However, it is also possible that De Niro was not amused with the implications in the CEO's joke since he referred to himself as the nerd among the brightest stars. Another likely move that De Niro could have taken offense to is when Butterfield pointed at him and singled him out as he commented about liking a certain part of "Godfather II" where De Niro's character killed Don Fanucci. After all, it is a bit rude to just point at somebody.

Then again, could it be possible that De Niro channeled his inner Vito Corleone since Butterfield expressed his liking for the character in "Godfather II?"

At least Butterfield took it in stride and still tried to find humor in it, as is evident in his tweet.

I just literally got trash-talked by Robert De Niro. "I don't know who the FUCK you are." #lifegoals pic.twitter.com/j9yT5ZiU4A

— Stewart Butterfield (@stewart) November 5, 2015

He also explained the situation that night.

@fooljay @SFGate I originally just thought he wasn't paying attention and misheard, but most people there thought he was just making a joke. — Stewart Butterfield (@stewart) November 6, 2015

The seriousness of the awkward situation was quickly dispelled because De Niro was quick to pull a 360 and praised Angelina Jolie to whom he was presenting The 2015 Entertainment/Film Innovator Award to.

Be sure to follow T-Lounge on Twitter and visit our Facebook page.