Reporter: Nascar ace jeff gordon is behind the wheel apparently taking an unsuspecting car salesman on a test drive like no other. Whoa, whoa. A. Agh. Reporter: Millions of youtube hits later a viral... See More
Reporter: Nascar ace jeff gordon is behind the wheel apparently taking an unsuspecting car salesman on a test drive like no other. Whoa, whoa. A. Agh. Reporter: Millions of youtube hits later a viral home run for pepsi max which starts out with jeff gordon showing up at the dealership in disguise with a hidden camera in his can of pepsi. Sort of gravitated toward the camaro. I don't know if I can handle it. I've never driven anything like this before. You are liable for any damages to the vehicle so please stop the car. Reporter: But is any of this real? A pepsi spokesperson said a stunt man actually did some of the driving. Please stop the car or at least -- Reporter: Refused to say whether steve is really a car salesman or an actor but stressed his reactions are 100% genuine. Stop the car. Stop the car right now! I started to suspect on the second viewing -- Reporter: This man, an auto enthusiast noticed some flaws among them rubber marks on the ground. There are multiple takes taken so I know that the salesman was an actor. I was told that by my source on the set. No matter what still exposure even if they're talking about it in a negative way. Reporter: Tweets suggest a lot don't care if it' or not. It's still a lot of fun to watch. It's a great ad. Oh my. ReporteS THE VIRAL PRANK The future of advertising? Pepsi has done it before with an old man called uncle drew, really the cleveland cavaliers' kyery irving in disguise upstaging some young bucks. I don't know how much longer you can keep it up without people realizing they're being tricked. Reporter: I'm talking about it right now and -- I'm going to kill you. Reporter: A real salesman might have had a heart attack and that would not be funny. Good morning, america, nick watt, abc news, los angeles. Something tells me we'll see more of these. If I was an actor -- doesn't matter. Even though he shared duties with the stunt driver gordon said it's the most fun he's ever had -- I like that too. Very, very funny.
This transcript has been automatically generated and may not be 100% accurate.