Darren Criss says coping with Cory Monteith's death has been difficult.

The 'Glee' cast have started filming the fifth season of the show, just two weeks after leading man Cory, 31, died from a heroin and alcohol overdose and Darren admitted they are all going through a tough time.

He told chat show host Conan O'Brien: ''Obviously it's been a very rough time. When you start picking up the pieces after something as tragic as this, and it's funny that you say that, you don't know how to breach it, we're picking up the pieces now and there's two things you gotta remember. One, is he was a really funny guy and he loved life. He always took care of his friends and wanted his friends to be happy. So it's only right that we, you know, try and start to smile again and laugh again. It's something that he would have wanted.''

While Darren was shocked by Cory's death, he is grateful he got to know the actor during their time on the show together.

He said: ''He was a joy. Wonderful guy. Personal note, he will be severely missed, but I'm just so happy that a guy like him got to touch as many lives as he did while we were lucky enough to have him.''