Cory Monteith

"Glee" actor Cory Monteith died of an overdose of heroin and alcohol, the British Columbia coroner's office said Tuesday.

With no obvious cause of death for "Glee" star Cory Monteith, the British Columbia Coroners Service says it will do further testing to determine how the 31-year-old died.

Cory Monteith, the  young actor who shot to fame in the hit TV series "Glee" but was beset by addiction struggles so fierce that he once said he was lucky to be alive, was found dead in a hotel room, police said. He was 31.