Frat boys: a segment of the male species that thrives on excessive binge-drinking and toying with the hearts and minds of college females. Usually between – but for some reason never limited to –the ages of 18 and 22.

Okay, so I made that definition up.

For decades, frat boys have spanned the scope of media, politics, sports, music, and even entertainment. BUT, did you know that a generous handful of Hollywood's hottest hunks were in fraternities? I did some digging and am happy to show you what these men were like during their glory days – the good, the bad, and the mullets.

Name: Ashton Kutcher

School: The University of Iowa

Affiliation: Delta Chi

Who knew this cutie was a former frat star? Our boy Ashton used to live it up in his Delta Chi days, and is quoted in a 2007 Cosmopolitan article saying “I woke up many mornings not knowing what I had done the night before. I played way too hard. I am amazed I am not dead”. We are too, Ashton. We are too.

Name: William "Brad" Pitt

School: The University of Missouri

Affiliation: Sigma Chi

Right there in the middle. Brad's luscious locks and even more illustrious smile have been able to stand the test of time, as he is still considered one of the most attractive men ever. But before he met Angelina and Jennifer Anniston, Brad Pitt liked to live it up with his boys...

...and apparently the Pi Beta Phi girls. We'd love to see you compete in Greek Week, Brad.

Name: William Ferrell

School: The University of Southern California

Affiliation: Delta Tau Delta

Who would've thought that someone with a serious face such as this would turn into one of the most celebrated comedians of our time? Come to think of it, Will Ferrel probably takes character inspiration from his frat bros on the daily. And rumor has it that he was caught streaking the USC campus a time or two with some other DTD's...

Name: Paul Rudd

School: The University of Kansas

Affiliation: Sigma Nu

LOOK at that mane. If any Sig Nu's ever needed to borrow a comb, they'd know that brother Rudd was the guy to ask.

Name: Luke Bryan

School: Georgia Southern University

Affiliation: Sigma Chi

One of America's favorite country stars learned his life lessons from his fraternity – shocker. Luke Bryan's days of shotgunning beers with his brothers in the southern sunshine may be behind him, but he'll never lose that youthful spark.

Name: James "Jimmy" Marsden

School: Oklahoma State University - Stillwater

Affiliation: Delta Tau Delta

A face that could break a million hearts (and probably did). In a world full of soft-smiled Chis' and Craigs, choose to be a Jimmy.

Name: Nick Lachey

School: Miami University – Ohio

Affiliation: Sigma Alpha Epsilon

Before he was the 98 Degrees front-man, Nick Lachey was a total frat bro. And we're almost positive some of his old college dance moves made it into a music video or two.

Name: Seth Meyers

School: Northwestern University

Affiliation: Phi Gamma Delta

The "Late Night" host definitely had a few late nights himself with his FIJI brothers. It's safe to assume this comedian was the life of any frat party.

Last but the opposite of least...

Name: Matthew McConaughey

School: The University of Texas at Austin

Affiliation: Delta Tau Delta

With his sand-blonde hair and slightly suggestive smirk, Matthew McConaughey could charm his way out of any missed class, bad grade, or girl trouble. We'd like to imagine him playing football on the quad with his boys, or cracking open a cold beer at the local bar after a long day...But really we hope to think he was just as wild back then as we are now.

And there it is: proof that you can actually peak after college. Who would've thought?