Cory Monteith, the 31-year-old heartthrob of Fox's musical-comedy television series "Glee," died of an overdose of heroin and alcohol, Canadian authorities said on Tuesday.
The British Columbia Coroners Service said in a release that post-mortem testing on the star, who was found dead on Saturday in a downtown Vancouver hotel room, died of "a mixed-drug toxicity involving heroin and alcohol."
However, it said Monteith's death was unlikely to have been intentional.
"There is absolutely nothing at this point, no evidence to suggest this is anything but the most sad and tragic accident," said Barb McLintock, a spokeswoman for the Coroners Service.
Monteith was found dead shortly after noon on Saturday in his room at the Fairmont Pacific Rim hotel. Vancouver police said they believed he was alone in the room after returning to the hotel early on Saturday morning.
Monteith was public about his struggles with substance abuse. In April, he completed voluntary treatment for unspecified substance addiction at a rehab facility. He had also been treated in a facility at age 19.
The actor, who was born in Calgary, Alberta and grew up in Victoria, British Columbia, told Parade magazine in 2011 that he had a serious drug problem during his teenage years for which he received treatment.
Monteith began his career in a number of small roles leading up to a recurring part between 2006 and 2007 in the ABC Family science-fiction drama "Kyle XY" and another role around the same time on the MTV series "Kaya."
"Glee," a show set in the small town of Lima, Ohio, was Monteith's breakthrough. It is centered on a high school glee club. Popular for its song and dance routines and big-name guest stars, the show has won Golden Globe, Emmy and Peabody awards.
Monteith played high school athlete Finn Hudson in the series.