Don't get too attached, Gleeks.

Ryan Murphy, creator of the hit Fox series "Glee," has revealed that the show plans on saying goodbye to some of its original cast members after the third season, when several main characters are expected to graduate from the show's fictional McKinley High.

"Every year we're going to populate a new group," Murphy said. "There's nothing more depressing than a high schooler with a bald spot."

This process already began in this season's premiere, with the introduction of Chord Overstreet as Sam Evans. The character was initially speculated to be a love interest for Kurt (Chris Colfer) but has since begun a relationship with cheerleader Quinn (Dianna Agron).

Many of the show's current crop of actors, including Cory Monteith and Mark Salling -- who portray glee club members Finn and Puck, respectively -- are already in their mid to late 20s, and Murphy believes that the show can persist with newer glee clubbers.

"I think you have to be true to the fact that here is a group of people who come and go in these teachers' lives -- they graduate and they're gone," he said. "If you can keep regenerating -- and I didn't think we could -- I didn't know if people would want those characters but they do,"

Murphy didn't specify which members of the original cast -- including breakout stars like Colfer and Lea Michele -- might stick around after the conclusion of season three. Both received Emmy nominations for their work in the show's debut season.

"When some of them finish their run at high school, it will be very teary episodes," said Murphy. "For me it will be particularly tough but a new crop (of actors) will come in."

However, it is speculated that the adult characters, such as glee club director Will Scheuster (Matthew Morrison) and cheerleading coach Sue Sylvester (Emmy winner Jane Lynch) will remain active players in the series beyond that point.

"Glee" airs Tuesdays at 8 p.m. ET on Fox.