Sad news out of Canada.
Cory Monteith, who played Finn Hudson on "Glee," was found dead in Vancouver on Saturday. He was 31.
Sources tell TMZ the actor was "clearly deceased" when police arrived at the Fairmont Pacific Rim Hotel around noon. Staffers alerted the authorities when Monteith didn't check out on time. An autopsy is scheduled for Monday.
Monteith candidly admitted to having substance issues in the past, and entered rehab earlier this year for treatment.
At the time of his death, he was dating his costar Lea Michele.
Fellow costar Matthew Morrison had a concert on Sunday night following Cory's death -- click here to find out how he honored his costar at the top of the show.
To see some of his most memorable performances on "Glee," click here.
Cory's friends and fans were stunned by the news of his death. Read the reactions they posted on Twitter below.
I just heard the news.This is so sad. My heart goes out to his family & friends, specially Lea Michelle.Rest in peace Cory
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.
While I only met him briefly on set, I remember him to be an extremely sweet guy. Tragic. RIP Cory.
Dot Marie Jones
I HAVE NO WORDS! MY HEART IS BROKEN CORY WAS NOT ONLY A HELL OF A FRIEND HE WAS ONE AMAZING MEN THAT I WILL HOLD CLOSE TO MY HEART FOREVER. I AM BLESSED TO HAVE WORKED WITH HIM AND LOVE HIM SO MUCH! MY HEART IS WITH HID FAMILY AND OUR WHOLE GLEE FAMILY! I LOVE YOU ALL!
GLEE (official Twitter)
We are deeply saddened by this tragic news. Cory was an exceptional talent and an even more exceptional person. He was a true joy to work with and we will all miss him tremendously. Our thoughts and prayers are with his family and loved ones.
RIP CoryMontieth. You will be loved. Always.
The guy I shot my first acting scene with. The nicest guy I've met. Can't believe it.
OMG!! My Cory...
I am totally heartbroken right now. I love Cory so much this hurts my heart. I hope my #glee family is ok right now. I love them all.
Its truly a sad day-an amazingly talented young man is gone.So sorry to the family,friends&fans of Cory Monteith.Such a good man.Truly.
Jesse Tyler Ferguson
I am so sad to hear about Cory Monteith. He was a lovely person with a ton of talent. My heart goes out to his family and friends. RIP Cory.
#RIPCoryMonteith... So unbelievably tragic. Please #prayforLea..
SO sad tonight...no justice for Trayvon Martin and now the sad news of Cory Monteith . Heartbreaking
Just heard about the death of Cory Monteith. So sad. Prayers 4 his family. Praying 4 Lea too! Words cant describe what they must be feeling
This is such sad news about @CoryMonteith - what an absolutely tragic loss of a very talented young man.
Really sad about Cory Monteith's passing. Saying prayers for friends and family, what a difficult time...
I am in shock about the horrible news of Cory Monteith's death. I wasn't lucky enough to know him but I am saddened today by this loss.
Terrible news these past couple days, and now today. RIP #CoryMonteith Gone Way too soon. My prayers are with his family ....
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.
I am shocked and deeply saddened by the heartbreaking news about Cory Monteith. My heart goes out to his family and Lea Michelle.
R.I.P. Cory Monteith. #Glee.
#CoryMonteith no words. Prayers. Thoughts w his family. This is terrible. Can't speak.
My heart breaks for the family, friends and life of Cory Monteith. Addiction is one of the worst culprits in a life unfulfilled and unrealized to its full potential.
What I will remember about Cory Monteith is that he was talented, funny and absolutely kindhearted. We lost a gentleman. RIP
So very sad to hear about the death of Cory Monteith. Sending prayers to his family and friends. May his memory be eternal.
This news of Cory Monteith's death just shakes me to my very core. So young. My thoughts and prayers to his family and friends.
I can't express how sad & horrible it is to hear about Cory Monteith.One of the best, kindest, guys I've ever met.Pray for him, & his family
Thoughts & prayers go out to parents and loved ones of Cory Monteith. So sad. Rest in Peace.
I am truly saddened to hear about Cory Monteith. What a talented and sweet guy. My prayers go out to his family and loved ones.
So damn sad.Ask for help. It gets better, believe me.
God I am so incredibly saddened by the death of Cory Monteith, completely shocked. My prayers goes out to all those who loved him.
omg. Met this sweet man. RIP.
I just heard about Cory Monteith.. Rest in peace, everyone close to him and affected by this loss you're in my prayers.
Rip Cory Monteith. Sad to see another young person go because of addiction. Blessings go out to his family and friends.
So sad to hear about Cory Monteith. Too many young people leaving this earth too soon. My heart goes out to his family n friends. R.I.P.
RIP Cory Monteith. Sweet man.... Gone far too soon. Peace be with you friend.
So incredibly sad.
Candace Cameron Bure
What?! My heart is sinking
I saw him a few weeks ago in NY, looking so happy. heartbreaking...
So sad to hear of Cory Monteith's passing. What an incredibly talented young man.. My heart goes out to Lea & his family.
RIP Cory Monteith. My thoughts and prayers are with you and your loved ones.
Such incredibly sad news about Cory Monteith. Brilliantly talented guy. Thoughts go out to friends, family and fans at such a sad time
RIP Cory Monteith... My sincere condolences to his many loved ones.
Shocked and saddened by the tragic death of Cory Monteith. All my love to his family, friends & girlfriend. #TooSoon
So heartbreaking to hear about Cory Monteith...my deepest condolences to his friends and family.
Wow! RIP Cory Monteith. such a nice guy. my thoughts and prayers go out to his family and friends. #RIP
This is devastating....my heart goes out to @CoryMonteith & his loved ones....& cast and crew of #Glee a tragic loss....#RipCoryMonteith
I'm gutted. Shocked and saddened to hear the news, my heart goes out to Cory's family and friends. Lets respect their space as they grieve.