KAMELOT backing singers Elize Ryd (also of AMARANTHE) and Alissa White-Gluz (also of THE AGONIST) filled in for NIGHTWISH vocalist Anette Olzon last night (Friday, September 28) at the Ogden Theatre in Denver, Colorado after Olzon was taken ill and had to be hospitalized.

Commented NIGHTWISH: "We were in hell [yesterday]. Vocalist in a hospital. Show about to be canceled... But nobody gave up an inch. With the help from the ladies Elize and Alissa from KAMELOT, we actually managed to pull of a relaxed and great show! The crowd doing the mass karaoke with the band playing was absolutely amazing. We were humbled and grateful at the same time. This is unity and help from friends and fans.

Fan-filmed video footage of last night's concert can be seen below.

"Anette is already recovering, thanks to the medical staff and whatever powers there exists. The shows will go on.

"We give our greatest respect to Alissa, Elize and the crowd in Ogden Theatre, Denver. You rule!!!"

NIGHTWISH's long-awaited "Imaginaerum" film — based on the band's album of the same name — will be released theatrically in Finland on November 23.

The movie will have its premiere on November 10 at Hartwall Arena in Helsinki, Finland, where the audience will be treated to both a full-scale NIGHTWISH concert and the first-ever public screening of the movie.

Eagerly anticipated around the world, "Imaginaerum" creates a musical fantasy world in the vein of David Lynch, Neil Gaiman, and Cirque du Soleil. The movie is an innovative mixture of story-telling and music, an extraordinary tale of the power of imagination… and what's ultimately important in life.

Shot and post-produced in Canada, the movie was directed by Stobe Harju and produced by Solar Films, and features appearances by all NIGHTWISH members. The screenplay is based on a wild vision that Tuomas Holopainen, the mastermind of the band, devised after the album "Dark Passion Play" came out in 2007.

The official soundtrack of the movie, "Imaginaerum By Nightwish: The Score", will be released on the day before the premiere — Friday, November 9. The album features 13 grandiose, unreleased re-interpretations of "Imaginaerum" tracks by Petri Alanko.

The "Imaginaerum" album was released in the U.S. on January 10 via Roadrunner Records.