Glee creator Ryan Murphy confronted Cory Monteith about his sobriety just weeks before he died from an alcohol and heroin overdose.
The 31-year-old actor died just three months after he completed a stint in rehab.
Murphy has now revealed he was instrumental in persuading the star to stop work on the show and address his problems in a clinic.
"As soon as I heard what was happening, when we had two episodes left to go, I brought him to my office where we had the intervention," Murphy has told industry website deadline.com.
"He said he wanted to finish the rest of the season, and I said absolutely not. We were not going to put a stupid TV show before his sobriety. I assured him he was not fired, that his job was secure, that he would leave today.