Throwback costumes seemed to be a trend this year. Kevin McHale, Naya Rivera, Heather Morris and Dianna Argon all dressed up as characters from the cartoon "Rugrats," Cute couple Jenna Ushkowitz and Michael Trevino went out as the Green Monkey's team from 'Legends of the Hidden Temple' and Matt Lanter was Zack Morris from "Saved by the Bell."
Zooey Deschanel, who dressed up as Neely O'Hara from "Valley of the Dolls" tweeted, "Last night marked my yearly tradition of putting a lot of effort into a Halloween costume no one can identify."
Can you identify all of these stars' costumes? Some of them are quite creative!