Monteith had been public about his battle with alcohol and drugs and had checked himself into rehab to battle substance addiction in March.
The Chicago Tribune reports Vancouver police officials said no cause of death was apparent at this time, but that Monteith had been dead for several hours before his body was discovered.
The actor’s publicist, Melissa Kates, released a statement, saying, “We are so saddened to confirm that the reports on the death of Cory Monteith are accurate.”
Monteith had been dating Glee costar Lea Michele for more than a year.
In 2011, he filmed a PSA for the Straight But Not Narrow campaign to help battle homophobia. Watch it below.