Britney Spears, Neil Patrick Harris, Ricky Martin: 'Glee' Guest Stars We've 'Gleeked Out' Over (GALLERY)
But in our Celebuzz gallery, we've selected the most unforgettable guest Gleek-sters from past seasons of the show. Whether it's Britney Spears dancing up a storm or a torrid romance involving the unexpectedly hilarious Gwyneth Paltrow, there's something in today list for everyone.
Take a look at the gallery above, and don't forget to watch Glee on Thursdays at 9 PM/8 PM CT.
What other stars have made guest appearances on Glee?
In addition to the stars featured in the gallery above, a number of top celebrities have shown off their musical talents on the hit show. This growing, eclectic list of celebs includes: Jeff Goldblum, Jonathan Groff (Spring Awakening), Kristin Chenoweth, Matt Bomer and Kate Hudson.