(Cover) - EN Showbiz - Lea Michele and her castmates Chris Colfer and Cory Monteith are leaving Glee.

The three regulars on the show have become household names since the start of the hit television series but their roles are going to written out after Season 3.

The show's co-creator Ryan Murphy says that he had no choice but to have the cast members of the high-school based musical show leave.

"You can keep them on the show for six years and people will criticise you for not being realistic," he told The Hollywood Reporter.

"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."

Lea, 24, and Chris, 21, are apparently both in agreement of the script idea even though it will put them out of a job.

"I involved Chris and Lea and they thought that was a good idea," Ryan shared. "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."

Ryan also added that "more characters are leaving than are staying". (C) Cover Media