After months of rumours that a character will die, the actor - who plays teacher Will Schuester in the hit musical show - revealed that someone unexpected will come to their demise and says the cast have already filmed the sad scenes at a funeral home.
He said: "Somebody's dying. Obviously I'm not going to tell you who it is, but it is no-one you would probably expect.
"The episode right before the finale is called 'Funeral'. We were actually at a funeral home yesterday, shooting all day. It was a very taxing day."
However, the 32-year-old star has told fans not to worry about him leaving the show, and denied that he is thinking of quitting.
While filming in New York this week he told reporters: "What is that? I don't know where the people get that stuff. No, [I'm] not at all [thinking of quitting]."
Meanwhile, extra Nicole Crowther - who was recently fired from the show for revealing spoilers from the upcoming prom episode - has said she regrets putting the details on micro-blogging website twitter.
She messaged her followers hinting at who would be prom king and queen, angering producer Brad Falchuck who told her she shouldn't expect to work in entertainment anymore.
She told the Los Angeles Times: "I had no idea it would Blow Up like this, I do regret it."