But to maintain the series' realism, creator Ryan Murphy has decided the current class should graduate in 2012 and leave the show for good.
In an interview on Ryan Seacrest's radio show, he says, "That is true. I don't think of it in terms of eliminating or replacing. Because I think the thing about this cast is people love them and they are incredibly talented. They've left sort of an indelible mark.
"The thing that I wanted to do and the cast wanted to do, we didn't want to have a show where they were in high school for eight years. We really wanted it to be true to that experience. We thought it would be really cool if we were true to the timeline."
But fans won't be too disappointed - Murphy insists the show's older leads Matthew Morrison and Jane Lynch will stay put.
He adds, "We've got Matt Morrison and Jane Lynch who will stay and be the male and female lynchpins of the series. But I think the fun thing about the show is it's a celebration of youth and talent and I think that just like with the original cast, I think finding those young unknown people and giving them an opportunity to break into the business and become stars is a really fun and exciting thing and is the spirit of the series."