Canadian actor Cory Monteith, 31-year-old heart throb of Fox's musical-comedy television series "Glee", was found dead on Saturday in his Vancouver hotel room, police said.
Police and paramedics found no signs of foul play and the cause of death was not immediately apparent, British Columbia Chief Coroner Lisa Lapointe told reporters at a news conference.
Monteith had talked about his problems with substance abuse.
In response to a question about whether Monteith died of a drug overdose, Vancouver Police Department acting chief Doug LePard said he would "not discuss anything that we might have found in the room at this time".
"We only notified family members about an hour ago, so we haven't even been able to have those conversations with them," he said.
Monteith, whose "Glee" character Finn Hudson was a high school football player turned enthusiastic glee club - or musical group - singer, was treated at a rehabilitation facility for an unspecified substance addiction this year.
The actor, who grew up in Victoria, British Columbia, told Parade magazine in 2011 about what he called a serious drug problem during his teenage years, and was first treated for addiction at 19.
Other people were in Monteith's Pacific Rim Hotel room on Friday night but evidence, including fob key entries, indicated he returned to his room by himself early on Saturday and was alone when he died, police said. He was due to check out of the hotel that day.
Monteith had been dead for several hours when his body was discovered by police and paramedics answering an emergency call, Lapointe said.
"The death of a young person is a tragedy for their family, friends and community," Lapointe said. "A sudden death is more shocking and our hearts go out to the family and friends who are mourning the loss of this young man."
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".
But "Glee," a show set in the small town of Lima, Ohio, was Monteith's breakthrough role. A big part of the show was his character's on-again-off-again romance with glee club star Rachel Berry, an aspiring entertainer played by Lea Michele.
Monteith and Michele followed in the footsteps of their fictional counterparts by dating in real life.
In recent episodes of the series, Rachel had jetted off to attend college in New York while Finn stayed in Lima, where he worked at his father's auto repair shop and later got involved in helping lead his former school's glee club.
In a statement on their "Glee" Twitter page, the executive producers of the show and Fox said they were "deeply saddened by this tragic news".
"Cory was an exceptional talent and an even more exceptional person," the Twitter message said. "He was a true joy to work with and we will all miss him tremendously. Our thoughts and prayers are with his family and loved ones."
Singer and former "Glee" actress Kristin Chenoweth said in a message on Twitter shortly after the police news conference, "You will be loved. Always."
An autopsy was set for Monday, LePard said.