Dennis Quaid rants like a pro: ‘I am doing my job here!’

Looks as if Dennis Quaid had one big bad day at the office.

Problem is, we don’t know where that big bad day happened, when it happened or whether what happened was real or staged.

But here’s a prima facie take on what happened: The “Vegas” actor was captured on cellphone video — apparently shot by a crew member on a movie or TV set — losing it completely in a profanity-peppered rant about how unprofessional those on the set were behaving.

“I am acting here and this ... wanders onto my set,” Quaid bellows, apparently after being instructed to “keep going” through the scene. “I can’t even get a line out until Dopey ... starts whispering your ear; you’re not even watching anymore.”

The video was posted on YouTube Friday with no context or details beyond the obvious: The actor freaks out and storms off set.

“Don’t ... ‘Dennis’ me,” the 61-year-old yells in response to a man who calls him by name. At this point he starts walking, and the video image drops down and stays down, showing the shoes of whoever’s doing the filming.

“I am doing my job here. I am a pro. This is the most unprofessional set I have ever been on ...,” the actor booms. “I’ve got these ... zombies over here that I have to look at. I have a bunch of ... staring at me. And this ... baby. This is garbage.”

After a final profane zinger, a door can be heard slamming. Presumably after Quaid walked through it.

Some were speculating Tuesday that the video was a prank, a la Jimmy Kimmel’s twerking girl, but it’s hard to imagine how anything with that much profanity would be suitable for network TV or very useful as a mainstream marketing tool.

Quaid’s words don’t exactly sound scripted either (though they do sound like something you could dance to, in this extremely profane mashup of his rant and that of Christian Bale, who in 2009 set the standard for caught-on-video actor outburts).

TMZ was flying the “It’s a stunt” flag after Quaid replied “C’mon, man” and had a hint (hint!) of a smirk when a videographer caught him on the street in New York City and asked him what had happened on set.

Coincidentally — or perhaps not? — streaming-video channel Crackle announced Tuesday in New York that “The Big Easy” actor would be starring in “The Art of More,” its first one-hour scripted drama. The 10-episode series, set in the world of premium auction houses, is schedule to premiere in the winter, according to Company Town.

Do you think Quaid’s rant was genuine or staged? Let us know in comments.

Follow Christie D’Zurilla on Twitter @theCDZ and Google+. Follow the Ministry of Gossip on Twitter @LATcelebs.