Glee, Lea Michele, Cory Monteith, Chris Colfer Glee, Lea Michele, Cory Monteith, Chris Colfer

Time for Lea Michele, Cory Monteith and Chris Colfer to start getting their cap and gowns ready.

After weeks of speculation about which characters will be graduating from McKinley High on Glee, co-creator and executive producer Ryan Murphy tells The Hollywood Reporter that the trio will depart after the upcoming third season.

Glee cast shake-up: Who's in? Who's out?

Michele, Monteith and Colfer are "not going to be back at all for Season 4," Murphy said. "You can keep them on the show for six years and people will criticize you for not being realistic, or you can be really true to life and say when they started the show they were very clearly sophomores and they should graduate at the end of their senior year."

He added that "more characters are leaving than are staying" and left an open question as to who else will say goodbye to New Directions for good. Exactly who's in and who's out for Season 4 will be revealed in the third season premiere on Tuesday, Sept. 20.

Glee's Ryan Murphy: Who's graduating, Season 2 backlash and next year's lack of guest stars

"We made that decision and I involved Chris and Lea and they thought that was a good idea," Murphy told THR. "They both trust the writing and trust me and felt that it would be great to have an open and closed experience for them to go out while they were on top."

Michele tweeted about the news late Wednesday: "We always knew we'd graduate in real time. It's all part of the plan and it's all good! It's going to make Season 3 amazing!!!"

Murphy said planning for the future will serve as a major theme this coming season. "I'm much more interested in Lea's character — not so much on her relationship with Finn, but more on what her dreams are beyond high school and how she plans on getting them."

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News of Michele, Monteith and Colfer's impending exits come just after Harry Shum Jr. and Colfer's on-screen boyfriend, Darren Criss, were promoted to series regulars for Season 3. This season will also introduce a new recurring character, who will be played by the winner of The Glee Project, to serve as a foil for Sue (Jane Lynch).

Are you sad Michele, Monteith and Colfer won't be back for Season 4? Will you still watch?