Holopainen says in their latest update video: "When I come up with a subject for the song, I always see it as a short movie. Each song is like a soundtrack for that movie in my head.

"From the moment I start writing I have the story in my head. I have a really clear vision of how the songs should sound at this point. Of course, they will change after band rehearsals and arranging."

The follow-up to 2011's Imaginaerum is set for release next year, although no details have yet been released. Meanwhile, Jansen has said her own band Revamp have to play second-fiddle to Nightwish's timetable - but they're not abandoning plans to make a third album.