"Glee" will look very different in Season 5, with four regular cast members leaving the show. According to TV Line, Heather Morris (Brittany), Mark Salling (Puck), Amber Riley (Mercedes) and Harry Shum Jr. (Mike) will not return as series regulars, but may make occasional guest appearances.

Dianna Agron's Quinn is also not expected to be back aside from potential guest spots; she was demoted to recurring status in Season 4 and only appeared in three episodes last year.

UPDATE: Melissa Benoist (Marley), Jacob Artist (Jake), Becca Tobin (Kitty), Blake Jenner (Ryder) and Alex Newell (Unique) have been upgraded to series regulars on "Glee," according to The Hollywood Reporter.

The characters have been on borrowed time since Season 3, when Puck, Mercedes, Mike and Quinn graduated along with classmates Rachel (Lea Michele), Finn (Cory Monteith), Kurt (Chris Colfer) and Santana (Naya Rivera). Brittany was accepted into MIT in the recent Season 4 finale and since Heather Morris is pregnant, the actress likely wants to focus on motherhood in the coming months.

An insider told E! News in May that the pregnancy made it "somewhat unlikely" that Morris would return as a series regular on "Glee" for Season 5, "however it's almost certain we will see her again 'in some capacity,'" the website reported.

"Glee" has been renewed through Season 6, but the Fox dramedy has dipped year-to-year in the ratings, since Season 3 averaged a 3.0 rating in the 18-49 demographic and 7.31 million viewers, while Season 4 averaged a 2.2 with 5.86 million total viewers.

A request for comment from Fox wasn't immediately returned.

Are you sad to see the original cast-members go?

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