Glee star Cory Monteith has checked into rehab for substance abuse. His rep says that the actor voluntarily admitted himself to a treatment facility for substance addiction. This isn't the first time Cory has struggled with substance abuse. He went to rehab back when he was only 19 years old. Co-star and girlfriend Lea Michelle also spoke to the mag to offer up her support of his decision. Good luck, Cory. We are pulling for you!