Real world dilemmas flummox musical cut-ups on GLEE as renewal hangs in the balance.

GLEE” hunk Cory Monteith has announced that he has entered into rehab for the second time! His first was when he was 19.

The 30-year-old, who plays football hunk Finn Hudson on the hit TV musi­cal, also has a criminal record for stealing money for drugs from family members when he was a teen. Meanwhile, the Canadian actor’s girlfriend and “Glee” co-star Lea Michele, 26, has managed to stay out of trouble – with the exception of a racy “GQ” photo shoot in 2010 – but she offered public support for her beau’s decision to seek help.

Cory isn’t the only cast member of “Glee” who has a checkered past. Al­though the stars appear to be young, beautiful, and successful beyond their wildest dreams, the former students of William McKinley High School aren’t as squeaky clean as they look!

“THEY ALL STARTED OUT WIDE-EYED and innocent for the most part, but once fame hit, certain actors’ egos blew up,” said a show insider. “The crew doesn’t know what to expect from day to day any­more – things have gotten out of control.”

Here’s a look at some of the other cast members who’ve had their troubles through the years:

Heather Morris, 26, a former Beyonce backup dancer who plays cheerleader Brittany S. Pierce, is reportedly pregnant by longtime boyfriend Tay­lor Hubbell, and no wedding plans have been announced. Morris was also caught up in a nude photo scandal in 2012 after her cell phone was report­edly hacked and topless photos were leaked online.

Resident “Glee” bad boy Mark Salling, 30, was slapped with a vicious sexual battery lawsuit in January in which ex-girl­friend Roxanne Gorzela claims he forced her to have sex with him with­out a condom in March 2011. In the lawsuit, filed by Gorzela’s attorney, she called Salling’s behavior “willful, malicious and despicable,” adding that it caused her “severe and substan­tial mental and emotional distress, humiliation, fear, apprehension, anxi­ety and anguish.”

The actor’s rep claimed Gorzela was just “looking to cash in” on Mark’s success.

Salling’s ex-girl­friend Naya Rivera, 26, a former Hoot­ers waitress who plays bi-curious cheerleader San­tana Lopez, was accused of throwing eggs and dog food at Salling’s Lexus and “keyed” it in a jealous rage after discovering he was hooking up with other women in 2010. Naya never confirmed nor denied the report.

Dianna Agron, 26, who plays popular Queen Bee cheerleader-turned-pregnant-teen Quinn Fabray, was also the focus of some serious drama after her “I Am Number Four” co-star and ex-boyfriend, 22-year-old Alex Pettyfer, got booted from a West Holly­wood nightclub in February 2011. Alex blew up, accusing Dianna of hooking up with “Black Swan” actor Sebas­tian Stan. Dianna packed her bags and moved out of the L.A.-area home they shared just a few days later.

“Glee” is in its fourth season. Their fifth season is currently being negotiated – if rehab and preg­nancies don’t get in the way.