Who knew Josh Duhamel worked at a grocery store in Los Angeles as a side job? Well he did...at least for one day.

Earlier today the 40-year-old actor tweeted, "Had some fun with @DietPepsi shoppers this weekend...Check it out," along with a link to the completed video.

Fun for him means breaking almost every rule a worker isn't supposed to do, such as riding around the store in a shopping cart and throwing bananas on the floor.

After watching shoppers on the surveillance cameras in the back room, the Transformers star decides to prank some of them and pretend that he isn't a celebrity.

"You're not really him, are you?" a shopper asks.

Another shopper tells him, "I think you'd be good at Westerns."

Since the video, presented by Diet Pepsi, is titled, "Check Out," Duhamel, wearing a black apron and name tag, decided to use the catch phrase as a pick-up line.

"Can I check you out?" he asks a blonde girl. After pretending to scan her, he says, "She's on sale!"

While some shoppers didn't seem blown away by their famous cashier, others were left speechless and in complete shock.

One girl even showed him her wallpaper on her cell phone, which just happened to be the actor himself.

"I had a blast 'checking out' Diet Pepsi fans at the cash register, it was like hosting my own candid camera!" Duhamel said in a press release. "Seeing the surprised reactions in real-time was really fun and I hope we gave a lot of shoppers a great story to tell their friends and family." 

Near the end of the video, Duhamel practices his parenting skills when he races down the aisle with a little girl.

Duhamel and his wife Fergie, who recently changed her last name to Duhamel, are expecting their first child in late August/early September.

Check out the Diet Pepsi video below!

Tags: Josh Duhamel diet pepsi grocery store commercial