It's a sad day for Glee fans around the world. "Glee" star Cory Monteith was found dead in his room at Vancouver's Fairmont Pacific Rim hotel Saturday. He was 31.

Vancouver police said the cause of death is not yet apparent, according to Reuters. Video footage shows the actor entering the hotel alone in the early hours of Saturday morning. He was found dead by hotel staff after he failed to check out on time and staff entered his room. Police report he was found dead at the scene and they do not suspect any foul play in the matter.

The star had been open about his fight against substance abuse which he says begin at the age of 13 with drugs. He voluntarily checked into a treatment facility earlier in April, making it his second time in rehab.

The actor's publicist, Melissa Kates, confirmed the news: "We are so saddened to confirm that the reports on the death of Cory Monteith are accurate. We are in shock and mourning this tragic loss."

During a press conference, Vancouver Police said the actor had gone out with friends on Friday evening, but video footage shows he was alone when he returned to his room in the early morning hours.

Many of the actor's "Glee" co-stars, along with dozens of other celebrities, took to Twitter to express their sadness over the tragic loss.

Singer and former "Glee" actress Kristin Chenoweth said in a message on Twitter: "You will be loved. Always."

Taylor Swift tweeted that she was "Speechless. And for the worst reason," while Rihanna posted that Monteith's death was "heartbreaking, my prayers are with all of his loved ones!"

Other tributes were posted by singers Lance Bass, LeAnn Rimes and Zooey Deschanel, who mourned the "absolutely tragic loss of a very talented young man."

Ricky Martin, who was a "Glee" guest star tweeted, "I just heard the news. This is so sad. My heart goes out to his family & friends, specially Lea Michelle. Rest in peace Cory."

His on-screen and off-screen girlfriend Lea Michelle has not yet commented on the tragedy. They were seen out and about as recently as  last month at a charity ball.