In 1999 Tarja took part in "The Evankelikumi" - a metal opera of Kaertsy Hatakka and the finnish band Waltari. It is a combination of modern dance, stage play and light shows. Producer Pekka Rahkonen: "Evangelicum is a breathtaking story about Good and Evil including all possible metaphores about these issues you can imagine. Happening in the Middle-Ages, telling about our times." The world premiere took place on October 15, 1999 at the Finnish National Opera Helsinki.



Source:
http://www.waltari.de/evangelicum/index.htm