Dennis Quaid freaked out, screaming, "This (blank) wanders onto my set! I can't even get a line out until Dopey (blank) starts whispering in your ear, and you're not even watching anymore!"
Video of his profanity-filled meltdown was leaked online. The 44-second clip looks like it was secretly recorded on a cell phone.
Quaid really let crew members have it on the set of a movie about the 2004 scandal involving former CBS Anchorman Dan Rather's now disputed report on President George W. Bush's military service.
The crew member taking the video apparently tried to hide what he was doing.
During the video, Quaid shouted, "I am a pro! This is the most unprofessional set I have ever been on. This is [expletive]!"
The video is now spreading around the world and generating headlines. But is it for real? Right now, opinion is divided.
The co-hosts of the Today show think it's fake. On The View, Nicolle Wallace said, "I think it's real and the filmer wasn't as brave as some others."
Whoopi Goldberg asked, "Have you seen any of his other, so-called 'real' videos? They're all kind of like that."
Watch: Jimmy Kimmel Move Kicks Off Late Night Ratings War
Many are speculating that it could be a Jimmy Kimmel prank. The late-night talk show host is well-known for setting up realistic-looking stunts that turn out to be hoaxes, like one video of a young woman twerking who accidentally sets herself on fire while twerking.
More than 30 million people watched the clip online only to realize later it was all set-up by Kimmel.
So, did Dennis Quaid really lose it? Or is he making it up? We'll know soon.