Since a few times many rumours had circulated about the line-up of Dimmu Borgir, with more precision about the drummer. Silenoz has just developed the things on the official sit by posting the next line-up :

Shagrath - vocals
Silenoz - guitars
Galder - guitars
Vortex - bass
Mustis - keys
Hellhammer - drums

While specifying :

"Hellhammer he is a hired hitman and will be playing festivals for us this year and on the upcoming album, and hopefully the world touring that will follow the new album"