Last year, 'Glee' creator and head writer Ryan Murphy brought new characters to the forefront, but not all of them will remain stars at McKinley High.

Chord Overstreet (Sam on 'Glee'), who joined the show for season 2, is not returning to the series as a regular this fall, according to

At the same time, breakout guest star Darren Criss (who plays Kurt's boyfriend, and Warblers' frontman, Blaine) has earned a promotion, and will be upgraded in the show's credits for season 3, joining the regular cast. Harry Shum, Jr., who plays the dancing love interest of Jenna Ushkowitz (Tina), will also become a regular.

Overstreet, 22, tweeted on Friday, "Well its been a good yr too bad its over, time for summer and starting fresh."