Via ShowbizSpy

Zac Efron wasn’t “that cool” during his school years.

The High School Musical star insists he hasn’t always been a heartthrob — and used to be a real nerd.

“I was pretty cool until about freshman year of high school and then it was downhill until I was about 17 and then something happened and it all came back,” Zac said.

“But that was pretty much the time that I was just average. I worked hard in school, got good grades. I was not that cool, so to speak. I mean, I thought I was cool but looking back — I really wasn’t.”