You have to start somewhere, right? We're so used to seeing our favorite Hollywood actors in major blockbuster films that it's often easy to forget where they came from. Before Michael Fassbender  was wreaking havoc as young Magneto, he was showing off his rippling muscles in 300. Before Jared Leto snagged an Oscar  for Dallas Buyers Club, he was axed to death by Christian Bale  in American Psycho. And before Johnny Depp  became Jack Sparrow and all his other crazy characters, Freddy Krueger was haunting his dreams. Wondering who else was in a popular movie without you even realizing it? Keep scrolling, and prepare to have your mind blown.
Source: Lionsgate , Warner Bros. 
Michael Fassbender, 300
If you can pull your eyes away from his abs for just a second, you'll see it's totally him.
Justin Long, Crossroads
Justin Long  and Britney Spears  totally shared a bed. Definitely something you'd never expect to say.
Ian Somerhalder, Life as a House
Ian Somerhalder  was only 22. He hadn't quite mastered the smolder he now uses in The Vampire Diaries.
Johnny Depp, Nightmare on Elm Street
The original came out in 1985! Raise your hand if you remember how good Johnny Depp  looked in that half shirt.
Ryan Gosling, Remember the Titans
Just look at those dance moves.
What's that, you say? One more for the road?
Joe Manganiello, Spider-Man
That's right. In the 2002 Spider-Man starring Tobey Maguire , Manganiello played Flash, and he had just as much wolf rage as he does on True Blood.
Jared Leto, American Psycho
It's a far cry from his Academy Award-winning performance as Rayon in Dallas Buyers Club.
Andrew Garfield, The Other Boleyn Girl
Truth be told, Andrew Garfield pulls off ye olde English garb almost as well as he pulls off the Spider-Man suit.
Matt Damon, Eurotrip
It might have only been a cameo, but it was still absolutely epic. There are no words.
Matthew McConaughey, Angels in the Outfield
And, of course, he had a hot shirtless  scene. You know who else was in Angels in the Outfield? Adrien Brody .
There he is!
Bradley Cooper, Wet Hot American Summer
Bonus point: that's totally Amy Poehler .
Matt Bomer, Flightplan
Yep, before he was stripping down in Magic Mike, Matt Bomer was a flight attendant in Flightplan.
Jimmy Fallon, Almost Famous
He was the manager!
Alexander Skarsgard, Zoolander
Three words: Orange Mocha Frappuccinos!
But that's not all. You know who else was in Zoolander for like, one second?
Oh, yes. That's James Marsden.
Jason Bateman, The Sweetest Thing
This movie came out just one year before Arrested Development first premiered.
Daniel Craig, A Kid in King Arthur's Court
The name's Kane. Master Kane.
Diego Klattenhoff, Mean Girls
Trying to figure out what else he's from? Diego was Mike Faber, Brody's best friend on Homeland. He's also one of the stars of Blacklist.
John Krasinski, Jarhead
The same year The Office premiered, John Krasinski  was rockin' a crew cut and glasses.
Tom Hiddleston, Midnight in Paris
It may seem obvious, but with so many famous faces in the film, it's easy to forget that Tom Hiddleston was F. Scott Fitzgerald. Even more shocking: Corey Stoll was Ernest Hemingway .
Maybe you're like, "I don't even know who that is." Well, if you take away his hair, you'd realize he plays Peter Russo on House of Cards.
Source: Netflix 
Vince Vaughn, Rudy
How cute is young Vince Vaughn , by the way?
Jesse Eisenberg, The Village
Before he invented Facebook in The Social Network, he was trapped in an M. Night Shyamalan movie.
Jake Gyllenhaal, City Slickers
Those baby blues were just as mesmerizing when he was a kid.
Brad Pitt, True Romance
Everyone remembers Thelma & Louise so intensely that they often skim right over stoner Brad.
Chris Evans, Not Another Teen Movie
It's a whole new side of Captain America. And let's not forget Not Another Teen Movie also features How I Met Your Mother's Josh Radnor .
There he is as the tour guide!
Seth Rogen, Donnie Darko
Seth Rogen  is almost unrecognizable as one of the bullies who terrorizes Donnie Darko.
Source: New Market Films 
James McAvoy, Wimbledon
Bonus: did you recognize Nikolaj Coster-Waldau, aka Jaime Lannister from Game of Thrones, on the right?
Ben Affleck, Dazed and Confused
Everyone's so caught up in Matthew McConaughey  and his iconic "alright, alright, alright" that they totally forget about Ben — with a paddle.
Jon Hamm, Space Cowboys
This guy is a far cry from Mad Men's Don Draper.
Justin Theroux, Romy and Michele's High School Reunion
That's not the only weird Justin Theroux role  we've suddenly remembered, either.
Jason Segel, Can't Hardly Wait
We've all spent so much time wondering which character we are  that we totally missed Jason Segel .
Benedict Cumberbatch, Atonement
Yep, before Benedict Cumberbatch's sexiness  was blowing us away, he was sporting a creepy mustache in Atonement.
Henry Cavill, Count of Monte Cristo
Can you believe this is the same man who would later play Superman?
Penn Badgley, John Tucker Must Die
With hair like that, we're totally starting to see why he was Gossip Girl.
Jon Stewart, Big Daddy
Yep, before The Daily Show, Jon Stewart  was acting alongside Adam Sandler .
Jim Parsons, Garden State
Like, he basically plays the same character as he does in The Big Bang Theory.
Chris Messina, You've Got Mail
With the hilarious credit of "Fox Salesperson."
Neil Patrick Harris, Undercover Brother
After Doogie Howser, M.D. but before How I Met Your Mother, there was this.
James Franco, Never Been Kissed
James Franco  was only 21 in this!
Chris Hemsworth, Star Trek
It's hard to believe this came out only two years before Thor.
Joaquin Phoenix, Parenthood
This came out in 1989, which means Joaquin Phoenix  has been making movies for 25 years!
Jonah Hill, I Heart Huckabees
You never would have guessed he'd later be nominated for two Oscars.
Robert Downey Jr., Weird Science
Iron Man  got his start in science back in 1985.
Elijah Wood, Back to the Future II
The year was 1989, and Elijah Wood  was 8 years old. Just look at him, and try not to melt.
Aaron Paul, Whatever It Takes
Back in 2000, Aaron Paul was causing mischief as Floyd.
Paul Rudd, Romeo + Juliet
Paul Rudd  in Clueless is totally duh, but we bet you forgot he was an astronaut in Romeo + Juliet.