'Glee' fans, we know you've been marking your calendars and happily the wait is almost over! The Fox hit is returning with a very big episode following Super Bowl XLV on Sun., Feb. 6 at approximately 10:30PM EST (time will vary depending on the game).

The New Directions gang will bust out Michael Jackson's signature hit 'Thriller' -- also the episode title -- and we've got the very zombie-heavy preview pictures straight from Fox. Ever wonder what Dianna Agron and Lea Michele would look like undead? Wonder no more. Plus, some very blue Katy Perry wigs!

Check out the preview pictures and the first commercial after the jump. And of course, spoiler warning.