Actor Cory Monteith, who stars as Finn Hudson on the Fox series Glee, has checked into rehab, PEOPLE has learned exclusively.
The actor "has voluntarily admitted himself to a treatment facility for substance addiction," his rep tells PEOPLE. "He graciously asks for your respect and privacy as he takes the necessary steps towards recovery."
Monteith, 30, has been open about his past struggles with substance abuse. He admitted in a 2011 interview that he had previously entered rehab when he was 19.
At the time, the actor said he hoped being honest about his struggle with substance abuse would help others.
"I don't want kids to think it's okay to drop out of school and get high, and they'll be famous actors, too," he said in 2011. "But for those people who might give up: Get real about what you want and go after it."
Glee star Lea Michele is supporting her costar and boyfriend Cory Monteith as he enters rehab for substance addiction.
"I love and support Cory and will stand by him through this," she tells PEOPLE exclusively. "I am grateful and proud he made this decision."
Michele and Monteith took their romance public in April of last year and have been spotted around Los Angeles together, most recently at a Los Angeles Kings game on March 23.
Michele, 26, has been quite vocal about her feelings for her beau, telling PEOPLE in 2012, "He really, really inspires me, and he motivates me and I think he's just so talented."
The actor "has voluntarily admitted himself to a treatment facility for substance addiction," his rep tells The Hollywood Reporter. "He graciously asks for your respect and privacy as he takes the necessary steps towards recovery."
Gleeis in the midst of shooting its fourth season. Production on the remaining two episodes is expected to continue as scheduled.
"Cory is a beloved member of the Glee family and we fully support his decision to seek treatment," 20th Century Fox TV, which produces the show, told THR in a statement. "Everyone at the show wishes him well and looks forward to his return."
During Glee's current season, Monteith's Finn Hudson has been struggling to find his way after high school. Most recently, the character stepped in to oversee the glee club while Matthew Morrison's Will Schuester went off to Washington. Upon his return, Finn realizes that he has what it takes to teach and will likely pursue that dream. His character was last seen in New York, where he showed up to fight for his "future wife" Rachel (Lea Michele).
Monteith and Michele have been a real-life couple for some time. They first publicly acknowledged their relationship a year ago.
"I love and support Cory and will stand by him through this," she tells THR. "I am grateful and proud he made this decision."
People first reported the news Sunday night.
It's not the first time Monteith, 30, has undergone a treatment program for substance abuse: He previously checked into rehab when was 19.
Monteith has played Finn on Glee since it debuted in 2009. He also has a role in the upcoming indie All the Wrong Reasons.