How much does the job pay? homework answers free Actor Cory Monteith known for his starring role as Finn on "Glee" has checked into rehabilitation People magazine reports. Monteith 30 has "voluntarily admitted himself to a treatment facility for substance addiction" his rep told the magazine adding that the actor asks for "respect and privacy as he takes the necessary steps towards recovery." It isn't the first time. Monteith has been open about his struggles with substance abuse in the past and previously admitted he checked into rehab for the same issue at age 19.