[7] The studio sessions proved to be a struggle due to the cultural differences and language barriers, but Dutch engineer Ronald Prent was brought in by Hellner to serve as a middleman between the band and the producer.
[7][8] Herzeleid faced a slow reception, but received a major popularity boost internationally in 1997 when two songs from the album were picked by director David Lynch for the soundtrack to his movie Lost Highway.
[5] Sehnsucht was released in 1997 and became a major international success, spearheaded by the singles "Engel" and "Du Hast", the latter being nominated for the Grammy Award for Best Metal Performance in 1999.
During Rammstein's hiatus in 2006, Hellner co-produced the band's lead guitarist Richard Z. Kruspe's side project Emigrate and their debut album.
During that same year, he formed the metal and classical project Bright & Black, featuring conductor Kristjan Järvi, the Baltic Sea Philharmonic and Eicca Toppinen of Apocalyptica.
[16] In 2024, Bright & Black released their debut album, featuring contributions from Tomas Haake and Dick Lövgren of Meshugga, Opeth guitarist Fredrik Åkesson, Watain frontman Erik Danielsson and ex-Entombed member Nico Elgstrand.