“What an absolutely tragic loss of a very talented young man,” tweeted Zooey Deschanel, star of another Fox show, “New Girl.”
Fox and the producers of “Glee,” including 20th Century Fox Television, called him an exceptional performer “and an even more exceptional person. He was a true joy to work with and we will all miss him tremendously.”
“We are in shock and mourning this tragic loss,” his representatives at Viewpoint Public Relations in Los Angeles said in a statement.
In April, Mr. Monteith admitted himself to a treatment facility for “substance addiction” and asked for privacy as he took steps toward recovery, a representative said at the time.
Miss Michele told People magazine at the time that she loved and supported him and was proud he was seeking help.
It was not Mr. Monteith’s first time in rehab. He received treatment when he was 19 and previously talked about his addiction struggles, saying he had a serious problem and took just “anything and everything.”
He told Parade magazine in 2011 that he was “lucky to be alive.”
The show, with its pop-music-based song-and-dance numbers and high-profile guest stars including Gwyneth Paltrow, became an immediate hit and made stars of its relatively unknown cast.
The series, which debuted in 2009, is in its fourth season.
On his Twitter account, Mr. Monteith described himself as “tall, awkward, canadian, actor, drummer, person.”
“I’ve never been afraid of working,” he said. “I’ve never been afraid of auditioning for jobs. Obviously, I’ve never been afraid of anonymity. I was happy (before ‘Glee‘). I’m happy now. I guess I’m well adjusted.”
According to his biography on Fox’s website, Mr. Monteith was born in Calgary, Alberta, and moved to Vancouver Island as a child. Before turning to acting, he held a variety of jobs, including Wal-Mart greeter, school bus driver, roofer and cab driver.