As fans and celebrities react to Glee star Cory Monteith’s sudden death, his on-screen stepfather is sharing his personal memory of working with the late actor.

Speaking to People , co-star Mike O’Malley says Monteith was a “great guy,” and a respectable actor.

"In real life, he was the coolest dude, generous, and a great friend to his pals," O’Malley says. “As Finn Hudson, he did what so many actors strive to do: authentically portray human behavior in a specific, understated manner, thereby eliciting laughter and creating camaraderie with his audience."

Monteith was found dead in his hotel room in Vancouver this past weekend. He had past struggles with drug abuse, but had recently completed treatment at rehab. Despite battling personal demons, O’Malley says Monteith was able to touch those around him with is empathy.

“If an ability to show others kindness and fostering fellowship are two qualities that all humans should strive for, Cory mastered them long before he died,” O’Malley said the late 31-year-old. “He deserved a long life. His death has rocked all of us at Glee ."

Though the cast and crew at Glee experienced shock at Monteith’s death, Kristen Johnston, of 3rd Rock from the Sun , told The Huffington Post that the young actor’s death did not surprise her.

"Whatever happened, I'm sure it was somehow involved with his addiction," Johnston said. "It's just terribly, terribly sad. However, it's completely not shocking to me."

The actress, and author of memoir Guts , has dealt with substance abuse and drug addiction throughout her life. She went on to say that while drug addiction is a serious problem among Hollywood actors, she does not believe such issues are more prevalent in wealthy Los Angeles circles than in the rest of the world. Johnston states that the media is to blame for presenting it as a "Hollywood only issue."

To watch the full interview with Kristen Johnston, check out the video below (her comments on Monteith occur beginning at 4:49):

Image: Fox