Tragic: Cory Monteith, pictured in Los Angeles on June 8, has died aged 31
The Canadian actor - who played Finn Hudson on the hit FOX series - was found on Saturday in his hotel room at the Fairmont Pacific Rim hotel in Vancouver.
Cory - who completed a stint of rehab in April for substance addiction - was last pictured with his girlfriend Lea Michele just last month.
The news was confirmed by Vancouver Police at a press conference on Saturday night.
No cause of death has been confirmed at this point, but there were said to be no implications of foul play.
Medical examiners will conduct an autopsy on Monday.
Acting Chief Doug LePard read in a statement: 'Shortly after noon today, the Vancouver Police received a call from the BC Ambulance Service regarding a sudden death in a room on the 21st floor of the Fairmont Pacific Rim Hotel at 1038 Canada Place in downtown Vancouver.'
Confirming: 'The deceased has been identified as 31-year-old actor Cory Monteith, who achieved great fame on the popular TV series Glee.'
Before giving out further information, LePard said: 'I want to pass on our condolences to the family, friends, castmates and millions of fans of Mr. Monteith.'
Cory had checked into the hotel on July 6 and had been due to check out on Saturday.
However, video footage had shown the actor returning to his room by himself after an evening out with friends on Friday.
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Recovery: Cory, pictured here on June 28, had left rehab in April after a one-month stint for substance addiction
Hotel: Fairmont Pacific Rim Hotel in downtown Vancouver where Cory Montieth died on Saturday
Room: One of the suites at the Fairmont Pacific Rim Hotel in downtown Vancouver where Cory had been staying
News channel CTV British Columbia tweeted the news shortly before it was confirmed saying: 'Sources tell CTV Glee star Cory #Monteith found dead today in Vancouver. Police expected to confirm at 10:30.'
Word had begun to spread on Twitter of the news late on Saturday night although there was no official comment made at that point.
Many believed it to be hoax, as it is not the first time news of his death had spread over the Internet.
Tragically, this time the rumours turned out to be true.
Real life couple: Cory and Lea attended the 12th Annual Chrysalis Butterfly Ball on June 8, 2013 in Los Angeles, California
Gone too soon: Cory was known for his role as Finn Hudson on the hugely popular series Glee
In a short statement, Cory's publicist Melissa Kates said: 'We are in shock and mourning this tragic loss.'
Just last month, the actor appeared to have put his troubles behind him after a brief spell in rehab.
Cory was seen with his girlfriend Lea Michele, 26, at LAX airport both smiling at cameras.
The couple also looked happy as they attended the Chrysalis Butterfly Ball on June 8 in Los Angeles.
RIP: Celebrities take to Twitter to tweet their condolences including stars of Glee
Confirmation: Vancouver Police ready a statement from Chief Doug LePard confirming the tragic news
Lea appeared to be particularly proud of Cory, who successfully completed a rehab stint in April for what his rep described at the time to be a substance addiction.
It was Cory's second trip to a treatment facility - his first stint occurred when he was 19.
'I love and support Cory and will stand by him through this,' Michele told People at the time. 'I am grateful and proud he made this decision.'
The pair were pictured in April after the actor had left rehab, going on holiday together.
Love story: Cory and actress Lea Michele developed a relationship off screen too
Celebrity outpouring: Kim Kardashian joined a long list of celebs who tweeted their sadness
In 2011, the actor sensationally admitted that he was 'lucky to be alive' after he went to rehab as a teenager for alcohol addiction.
Cory admitted he skipped school to get drunk and smoke pot when he was just 13-years-old and quit his education at the age of 16.
By the time he was 19, the TV singing sensation was undergoing a stint in rehab to battle his demons.
Speaking about his former drug habit, the actor said he did 'anything and everything - as much as possible. I'm lucky to be alive.'
Co-star: Fellow Glee actor Chord Overstreet was pictured in NYC on the day of the tragic news
Cast members: Jane Lynch was also spotted in NYC on the day of the news