Chris Klein was already 20 when he played all-American lacrosse-player Oz, one of four friends trying to get laid by prom night in "American Pie." But the movie's hijinks and pranks weren't far from his real-life experience in high school. In the latest episode of "When I Was 17," airing Saturday at 11 a.m., Chris reminisces about a prank that was played at his expense in high school.

"I went to public school, but I myself had a uniform, which was a white T-shirt, loose blue jeans and Airwalk shoes," says the actor, who is reprising his Oz role for next year's "American Reunion."

"Oh, and then there were the necklaces," he adds, recalling the beaded necklaces in school colors that were made by the cheerleaders. "I was a huge fan of the necklaces."

Because the actor wore the same outfit without fail every single day, his fashion sense was something of notice for his fellow classmates.

"One day, I walked into school and all of a sudden there is a bit of an uproar and everyone is clapping and laughing and having a good time. I look around and nearly everyone in my class was dressed exactly how I dressed every day," he says. "It was dress like Chris Klein day."

His whole class showed up to school wearing white T-shirts and blue jeans, making sure not to forget the key element: the beaded necklaces.

His classmates punked him for sure, which probably made acting in "American Pie" a piece of cake.

For more stories from Chris' youth, don't miss the new episode of "When I Was 17," also featuring [article id="1670465"]Amy Lee[/article] and [article id="1670514"]Theophilus London[/article], airing Saturday at 11 a.m. ET on MTV.