Back before Adam Levine was the suave, impeccably coifed frontman for Maroon 5, he was less than smooth and hardly well-groomed.

But that's actually putting it mildly, because as Levine reveals on Saturday's episode of "When I Was 17," the future Grammy-winner was totally freaking repulsive.

"When I was 17, I was gross," he admits on the show, airing at 11 a.m. ET/PT on MTV. "My hair was long and really ratty and nappy. [I wore] huge, oversize flannels that didn't fit [and I had] a goatee. Like a bad version of Ethan Hawke in 'Reality Bites.' "

Now that we know all of this, Levine's current obsession with his hair begins to make sense. As he told us last month, he is very particular about who clips his locks and was sad to see his favorite stylist — none other than Justin Bobby of "The Hills" fame — give up his day job.

"I don't know quite how to say this — I've got to say this delicately — but the man is the most incredible hairstylist ever," Levine said. He really is. Justin, you're a genius. He cut all our hair for a long time, and then one day, mid-cut, he was like, 'So I think I'm going to do this show,' and it was called 'The Hills.' "

But long before he met Justin, and long before he had any clue that he'd go on to sell nearly 15 million records, Levine was just a dorky, grunge-ified wannabe. Of course, that's not to say the guy was without a hint of charisma, however goofy he actually was. He was charming enough to find a high school sweetheart and to convince his math teacher to give him a C+ even though he was totally failing the class.

To find out what happened with his teenage love and why he couldn't master long division, check out this Saturday's episode of "WIW17."

"When I Was 17" — this week featuring Adam, Swizz Beatz and Kathy Griffin — airs Saturday at 11 a.m. on MTV.