12/04/2013 06:01 pm ET Updated Jan 23, 2014

Ryan Murphy Invites 'Glee' Original Cast Back For 100th Episode

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The 100th episode of "Glee" may not be until March, but details are already being announced for the giant celebration.

This week, Ryan Murphy sent out a tweet announcing all of the original cast members of the series were invited back for the 100th episode:

Since his initial tweet, Murphy has updated fans on which McKinley High Gleeks were returning. So far Heather Morris, Harry Shum Jr., Mark Salling and new "Dancing With the Stars" champion Amber Riley have been confirmed for the episode.

The original cast recently reunited for a more somber reason when they mourned the death of Corey Monteith, who played Finn on the series. The only original cast member who didn't appear in the episode was Dianna Agron, sparking rumors that she was not on good terms with her former "Glee" family.

This season has been turbulent for the once mega-popular series. Aside from Monteith's sudden death, the series has also experienced a ratings decline resulting in the November episode "A Katy or A Gaga?" being the lowest rated episode of the show's entire five-year run.

The 100th episode of "Glee" is scheduled to air March 18 on Fox, and don't forget you Gleeks can vote for which songs you would like to see performed on the special episode.

"Glee" airs Thursdays at 9 p.m. on Fox, and will be switching to Tuesdays at 8 p.m. starting in February.