This Is The End follows six friends trapped in a house while the world comes to an end: the land is caving in, there’s fire everywhere and what appears to be a dragon is reeking havoc over everything.

Seth RoganRogan reckons the Backstreet Boys were the perfect choice

So it makes sense that The Backstreet Boys make a cameo at the end. And according to Seth Rogan, the co-creator of the apocalyptic comedyр in which he and his actor friends star as themselves, it was the best way to end the film. He told Den of Geek: “Honestly, it took us forever. We probably knew in August or September that we needed to fill the new ending, and it took us until January to actually come up with what it should be. It took us forever – months and months and months of just spitballing what it could be. We had to write something.”

This is the End has faired quite well with the critics so far, with an overall rating of 81% on Rotten Tomatoes. Director Evan Goldberg revealed that they asked Morgan Freeman to cameo as God but he turned them down – he’s done that role so many times now, it’s probably enough for a lifetime. Rogan added of the strange cameo at the end (of This is The End): “And then the Backstreet Boys idea came and it just seemed like the funniest, most original and weird way to end the movie. And it’s potentially the most crowd-pleasing way to end the movie – that was our biggest problem. It didn’t end on a giant uproarious note.

James FrancoFranco's still thinking about it

“The movie’s so crazy that audiences thought the ending was too normal. People wanted it to go to an even crazier place. That just took us a really long time to think of.” You can make your own mind up about the film when it comes out on Jun 28, 2013. That’s tomorrow!