The 31-year-old Glee star was found dead at the Fairmont Pacific Hotel Saturday in Vancouver, leaving Hollywood and Glee fans alike rocked by the news of his passing.
Monteith's girlfriend Lea Michele has kept mum following the news of his death, but her rep issued this statement to E! News this morning:
"We ask that everyone kindly respect Lea's privacy during this devastating time. Thank you."
Take a look at what more stars had to say:
Katy Perry: Rest in peace Cory. My heart goes out to his family and loved ones. Our prayers are with you.
Adam Shankman: I will always cherish you in my heart. Thank you for so many wonderful days. I love you CM ...
Glee's casting director Robert J. Ulrich exclusively tells E! News "I'm heartbroken. Cory was extremely talented, but more importantly he was genuine, a truly nice person. He will be greatly missed."
Paula Abdul: I am shocked and deeply saddened by the heartbreaking news about Cory Monteith. My heart goes out to his family and Lea Michelle.
Sarah Shahi: So tragic to lose Cory Monteith. My heart goes out to his friends and family. RIP
Josh Groban: While I only met him briefly on set, I remember him to be an extremely sweet guy. Tragic. RIP Cory.
LeAnn Rimes Wow, just read the news about Cory Monteith. How sad, way too young. I hope he's at peace. Prayers go out to his family & friends.
Melissa Gilbert "@ENews: Cory Monteith Found Dead at Age 31" what?! How horribly tragic. My heart breaks for his family and friends.
Neil Patrick Harris How sad to read about Cory Monteith passing away. What a shame. He was a lovely, kind, talented guy and will be missed.
Richard Branson: #RIPCoryMonteith, he was a beautiful soul, committed to ending youth homelessness with @virginunite @virginmobilecan
Ricky Martin I just heard the news.This is so sad. My heart goes out to his family & friends, specially Lea Michelle.Rest in peace Cory #RipCoryMonteith
Ellen DeGeneres My heart breaks for the friends and family of Cory Monteith. What a loss.
John Stamos: First day on Glee he said to me, I can't believe I'm working w/Uncle Jesse-I can't believe i'm writing this tweet. Heartbreaking. RIP Cory. We talked about how lucky he felt to be alive-and sober. We talked about playing drums. Glad i knew you Cory.