Jane Lynch, Chris Colfer, Amber Riley and Darren Criss are set to appear on The Glee Project's current second season.
The Oxygen reality programme consists of contestants auditioning for a role in the Fox show Glee.
The winner's prize is an appearance on the popular show in a seven-episode arc during the next season.
Glee stars Lynch, Colfer, Riley and Criss will act as mentors to the season two contestants, according to TV Line.
Lea Michele, who plays Rachel Berry on Glee, previously made a cameo on season two.
The Glee Project airs on Tuesdays at 10pm ET on Oxygen.
Last month, Glee wrapped up its third season with a high school graduation.