Long before the stars attended events like the Oscars and Grammy Awards, the biggest thing on their calendar was prom night!
With "Glee" airing its "Prom-asaurus" episode tonight on FOX, we did some digging to find out what the celebs out there now looked like for their big nights back in the day.
Britney Spears, Ryan Seacrest, Fergie, George Clooney, Halle Berry and more ... see what they looked like at their own high school dances and find out which of them were crowned Prom King or Queen!
Check out a sneak peek at the prom episode of "Glee" below:
