Throughout his career, Lilja has continued to play classical music alongside rock, metal, and crossover projects.

In 1993, he was accepted into the Sibelius Academy's University-level program as a student of Dr. Raimo Sariola and Prof. Arto Noras.

Within a year, Apocalyptica was founded and signed to Finnish indie label Zen Garden, and released their debut album Plays Metallica by Four Cellos in 1996.

[4] Later that year, Hevein disbanded, promising to regroup if funding to finish their latest album ever materialized.

[5] In 2007, Lilja began performing with former Nightwish singer Tarja Turunen, as she launched her solo career.