All of “Glee’s” main cast members have agreed to return for the show’s fourth season. Though leads Lea Michele and Cory Monteith will appear in more episodes, Matthew Morrison, Jane Lynch, Chris Colfer, Naya Rivera, Kevin McHale, Darren Criss, Amber Riley, Jenna Ushkowitz, Jayma Mays, Dianna Agron, Mark Salling, Harry Shum, Jr. and Heather Morris will also be making appearances. The Fox TV series tackles topics of sexuality, insecurities, relationships and other social issues through the lives of various high school glee club students.
