Speaking with U.K.'s Metal Hammer magazine, lhsahn explained how this new reunion came to pass. "Me and Samoth were talking and the 20th anniversary of '…Eclipse' came up," he said.

"It's no secret that I've been reluctant to do the reunion stuff, because I want to be clear on my priorities as a solo artist.

"People ask us for EMPEROR shows all the time, and as a fan I can relate to that sort of nostalgia, but I'm much more involved in my current work. But now that I feel I've established a more solid foundation for my solo stuff, it was easier for me to appreciate the thought of celebrating this album that was such an important starting point for us."

Ihsahn's fifth solo album, "Das Seelenbrechen", will be released in North America on October 21 via Candlelight Records. The CD is described in a press release as "a bold and adventurous recording that is a musical contrast to the progressive shades and saxophone augmentations of the EMPEROR vocalist/guitarist's previous two albums (2009's 'After' and 2011's 'Eremita'). The album is every bit as dark and destructive as the artist's previous work but is far more disorientating and disturbing than anything he has attempted in his past."

"In the beginning of my solo career, I created more of a barrier between EMPEROR and my solo work," Ihsahn told Metal Hammer. "But over the last few albums, I've been able to tap into more and more of that old black metal feeling. It's such a fundamental part of my creative self. Even if the arrangements and form of my music are very different these days, I feel the source in its pure form is very much the same as when I first started out."

He added: "When EMPEROR play at [the festivals around the world] next year, I want to be able to tap into that and perform those old songs with the same conviction and authenticity as before."

The news of EMPEROR's appearance at Wacken Open Air was announced on August 2 at this year's edition of the festival at a press conference which was attended by Ihsahn and Samoth.

EMPEROR released its swansong, "Prometheus - The Discipline Of Fire And Demise", in September 2001. It was an epic and progressive metal album that once and for all marked EMPEROR as one of the most adventurous and gifted black metal bands of all times. In September 2005, EMPEROR surprised all with an unannounced appearance in Oslo. Following the three-song performance, the band announced additional concerts that would include a visit to America; marking the second trip to the States in the band's legendary career. Fans flocked to New York City and Los Angeles to witness the sold-out performances. In 2007, additional shows would see the band return to the U.S. for a repeat performance in New York City, a stop in Chicago, and what would be their final American performance in Los Angeles.