Evan Goldberg has revealed that he and Seth Rogen wanted to get more celebrities for This Is The End, such as Edward Norton and Cameron Diaz.
The ensemble comedy stars Seth along with friends James Franco, Jonah Hill, Jay Baruchel and Danny McBride all playing versions of themselves when the apocalypse hits, with appearances from Michael Cera, Rihanna, Emma Watson and more.
"We're friends with Edward Norton and he couldn't make it due to scheduling," admitted Evan, who directed and wrote the movie with Seth.
"Bill Hader couldn't make it because of Saturday Night Live, Seth's friend Elizabeth Banks couldn't make it. There was a handful of people but it was always scheduling - they wanted to come. Cameron Diaz really wanted to be there but she couldn't make it."
He hinted there could be a sequel, adding: "It's a bummer, but next time..."
The Canadian duo, who sat in the director's chairs together for the first time, said recruiting the star-studded cast was remarkably easy.
"Getting people on board creatively was not a problem, getting people scheduling-wise was a living nightmare," Evan continued.
"You got James Franco flying around the world to make a movie, teaching about movies, doing some art, doing some modelling, Craig Robinson was on a TV show and Jonah is a super-busy guy so it was really hard to get everyone together.
"But creatively, everyone was just down. We didn't go to anyone who wasn't excited - we only wanted people who were ready to rock. Even the Backstreet Boys," he added.
:: This Is The End opens in cinemas on June 28.