"Glee"'s farewell episode to its fallen star Cory Monteith will air next week, and Ryan Murphy says it was "incredibly difficult" to film.
"I locked [the episode] today. It was incredibly difficult to work on. It was very difficult to shoot," Murphy told E! Online. "I mean, the interesting thing about that show is that those actors and the creators really, really loved Cory. The episode is called 'The Quarterback,' and you know Cory really was that, to that group of people and to me particularly. There was nobody on that crew that did not like Cory."
Murphy added that shooting sometimes had to halt because the cast and crew couldn't stop crying.
A number of cast members who are no longer regulars on the show will return, including Amber Riley and Mark Salling. Murphy said even more actors wanted to reprise their roles to pay tribute to their friend.
"Iqbal [Theba], for example, who plays the principal and is now the janitor, was not written into that episode, but personally called up Brad and I and said, 'For him, I want to be in it,'" Murphy said.
Check out a promo for the show, featuring Lea Michele singing "Make You Feel My Love," below.